"Apple has issued a warning to iPhone customers regarding iPhone 3G and 3GS devices overheating.
Sporadic reports have hit internet blogs and gadget sites this week regarding overheating issues with new iPhone 3GS models. Reports from The Telegraph suggest that dozens of users have reported overheating issues. According to some owners the device becomes so hot that it's too hot to pick up and the casing on white 3GS models has turned pink for some.
Several posts to Apple's iPhone discussion forums appear to confirm these early reports. According to PC World, one of their own writers claims "I became aware the handset had become very hot. Very, very hot -- not just on the back, but the entire length of the front face, too".
French blog Journal Du Geek posted an image of a white iPhone 3GS earlier this week showing that the back of the device had discoloured to pink due to excessive overheating."