iPhone battery should never need to be replaced

[.: Mac :.]

“Most iPhone users will realize, as most iPod customers realized, that they never needed to replace their batteries,” Joswiak said.

For those who do eventually need to replace the iPhone battery a few years down the road (assuming they haven’t upgraded to a new model by then), Apple will offer a battery-replacement program. If your iPhone’s battery dies young (i.e., within the first year), then you’re covered by Apple’s warranty and the company will replace your battery for free.

And my guess is that by the time most original iPhone batteries are running out of juice, there will be many third-party companies who will offer to swap out your battery at a lower price than Apple’s official offering.

http://www.macworld.com/weblogs/macword/2007/07/iphonebattery/index.php