PC World, Wired, and other media outlets have reported that the new iPhone 3G S models have been running a little hot—hot enough to turn their white plastic cases brown, according to Wired  .
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Apple Support has acknowledged an overheating problem with both the 3G S and 3G phones, when they "run certain applications in hot conditions or direct sunlight for long periods of time, such as GPS tracking in a car on a sunny day or listening to music while in direct sunlight."

This problem may be limited to specific lots of phones, as such problems have not turned up during our tests, which are still ongoing.

Besides feeling hot, symptoms of an iPhone suffering from heat exhaustion may include a dimming display and a weak cellular signal. The most-obvious sign is an on-screen message "iPhone needs to cool before you can use it" (see image at right).

We'll keep you posted as the story unfolds. In the meantime, please let us know if you've experienced an overheating problem with your phone. —Mike Gikas

Just released yesterday, Mozilla’s latest version of its Firefox browser for Mac and Windows is full of new features, from enhanced privacy to new video standards. We haven’t formally reviewed Firefox 3.5, but here are a few features that we think are interesting:

Private browsing mode. Enabling this feature is supposed to remove any trace of the Web sites you visit while in this mode. No cookies, history, or any other trace of your visit is saved. Other browsers, such as Internet Explorer 8 and Google Chrome, also have this option.

Location-aware browsing. This one seems like the opposite of private browsing. It tells Firefox where you are so it can provide more-targeted information. Fortunately, you can turn it off at will.

Open video and audio. No more plug-ins necessary for viewing video and listening to audio online.

Speed. Mozilla says Firefox 3.5 is twice as fast as Firefox 3, and 10 times faster than Firefox 2.

You can download the new browser here. —Donna Tapellini

Things are once again cooking in CR’s DVD test labs, where we’re putting 11 new high-def Blu-ray players through their paces. All the new players we’re testing are BD-Live models that can access extra online content from the movie-studio’s servers, or download firmware updates from the manufacturer when new features are available.

Some of the models also offer access to additional Web-based content, such as movies from Netflix and Amazon Video on Demand, videos from YouTube, or streaming music from services such as Pandora.

These models will be part of the latest Blu-ray player Ratings (available to subscribers), which should be posted in a few weeks.

Here are some comments on the models currently being tested:

JVC XV-BP1: JVC’s first Blu-ray player can play back high-def AVCHD video files shot with a camcorder, and can internally decode DolbyTrueHD and DTS-HD Master lossless audio formats.

LG BD390: The only model we’ve tested with built-in Wi-Fi (802.11n, draft version), so it can wirelessly connect to the Internet via a home network. It includes LG’s NetCast online access for streaming movies and videos from CinemaNow, Netflix, and YouTube.

Oppo BDP-83: Oppo’s first-ever Blu-ray player is a true “universal” player that can play all types of discs, including high-resolution multichannel SACD and DVD-Audio titles.

Panasonic DMP-DB80: This feature-laden player includes Panasonic’s VieraCast online service, with access to videos from YouTube, digital photos from Picasa, and other Web-based content. It can internally decode Dolby TrueHD and DTS-HD lossless audio, and has 7.1-channel analog outputs. It includes an SD card slot, and can play back high-def AVCHD video files shot with an HD camcorder.

Philips BDP5010: This is a “BD-Live-ready” Blu-ray player, meaning it requires an optional 1GB of memory to use the feature. It has a unique look, with silver trim accents encircling the face of the player.

Pioneer BDP-320: Pioneer’s step-up Blu-ray player has a few extra features, including 13 separate video picture-control adjustments, internal decoding of Dolby TrueHD and DTS-HD lossless audio, and 7.1-channel audio outputs.

Samsung BD-P4600: A striking-looking player with a unique, flat design that allows it to be wall-mounted. It has a red translucent finish that matches the Touch of Color cosmetics of many Samsung TVs. The player comes with a Wi-Fi adapter (a USB wireless dongle) for connecting to a home network, and can access Netflix instant videos and Pandora Internet radio streams.

Samsung BD-P3600: This more conventional-looking player is functionally the same as the BD-P4600, but costs $100 less. It also has more connectivity options, including a component-video connection, which the P4600 lacks.

Sharp BD-HP22U: A step-up player that comes with 2GB of memory, which is 1GB more than most. It has a quick-start feature said to greatly speed up load times.

Sharp BD-HP16U: An entry-level BD-Live-ready Blu-ray player from Sharp that requires an optional 1GB of memory to use BD-Live. Like its sibling, it has a quick-start feature to speed up load times.

Sony BDP-S360: An entry-level Blu-ray player that can internally decode of Dolby TrueHD and DTS-HD Master audio formats. Like other BD-Live-ready players, it requires an optional 1GB of memory to use BD-Live.

As we mentioned, the new Blu-ray Ratings should be posted in a few weeks. We'll let you know when they're ready, so check back with our blog soon. —James K. Willcox

If you buy a new computer from Dell or HP in the next few months (or bought one since June 26), there’s a good chance you’re eligible for a free upgrade to Windows 7 when it becomes available in October. If you’re still shopping for a PC, be careful which version of Vista or XP you buy with it, because your choice will impact the Windows 7 version you’re eligible for; in some cases, you won’t even be able to upgrade free.

To get a free upgrade from Dell, you must buy an eligible system between June 26 and December 31, 2009. Get the system with Vista Home Premium 32-bit and you’ll be able to upgrade to Windows 7 Home Premium 32-bit when it’s available.

But if you buy a PC with Windows XP (because you want to skip Vista altogether), make sure you get the version that Dell calls Windows Vista Business Bonus –Windows XP Professional Downgrade. That will get you a free Windows 7 Professional later. If you get XP without that official downgrade, you’ll have to pay for any upgrade to Windows 7 later. Also avoid Vista Home Basic and Vista Starter Edition; neither of those qualify for the free upgrade.

HP’s program is similar to Dell’s. You must buy an eligible system until January 31, 2010; it needs Vista Home Premium, Vista Business, or Vista Ultimate (or the official XP Downgrade).

Other manufacturers are offering similar programs. —Donna Tapellini

The iPhone 3G S tops our new smart-phone Ratings (available to subscribers), with strong performance in everything but voice quality, an area in which few phones score well. It's not a runaway winner, though. A number of other phones ranked close to the iPhone, including the Palm Pre, which turned in a fine performance, as we expected from our head-to-head review of these two highly publicized rivals.

The phones vary significantly in how they achieve their high scores. The iPhone 3G S edged out high-scoring competitors such as the Palm Pre and BlackBerry Storm thanks to a superior display, reinforced by top-notch multimedia, navigation, Web browsing, and battery life. However, the Pre, the Storm, and other BlackBerry models bested the iPhone in messaging, and the Pre, with its new deck-of-cards handling of multiple applications, is a superior multitasker.

To better display those differences, we recently added more attributes to our Ratings and put more emphasis on the display, ease of navigation, and multimedia and messaging prowess. In turn, we've somewhat reduced the contribution of talk time (as reflected in our battery life results) and voice quality, in part to reflect the growing importance of non-voice use of smart phones.

The iPhone 3G and some other older phones have moved up due to these changes, while others, including the Samsung Blackjack II and BlackBerry Pearl Flip, have dropped in their ranking.

One of the few changes to our test protocol involves phone sensitivity, as one reader already noticed and commented on. During our Ratings revamp, we concluded that our existing tests of this attribute no longer adequately replicated real-life reception experience. Creating reliable reception tests has become steadily more challenging as smart phones add more tasks and use a growing range of reception technologies.

We've removed sensitivity scores from our Ratings while we develop tests to more accurately evaluate this attribute. Until then, we suggest anyone concerned about this (like the reader who commented on our blog) inquire about return provisions for phones, and take advantage of them as needed.

In addition, we're wrestling with ways to further evaluate phones' speed and versatility—growing concerns as the devices acquire more sophisticated operating systems and a host of third-party applications.

Such challenges are not unique to smart phones; they crop up periodically for all products, as they, and consumer expectations for them, change. Smart phones are among the most complex products we test, and perhaps the most subject to personal preference. Their Ratings have prompted debate and sometimes disagreement in the past. We welcome your comments and questions on the changes we've made this time around. —Paul Reynolds