Changing an iPhone 4 battery

Rick Broida just published a Cnet review article on replacing his iPhone 4 battery. Techies have been doing their own repairs since the beginning of course, but I hope this encourages others to consider their options.

How I replaced my iPhone 4S battery for $8
Apple may not make it easy to replace an iPhone’s battery, but that doesn’t mean you can’t do it. For cheap. And it takes only about 20 minutes.

Talk about an inconvenient truth: right around the 12-month mark, your iPhone battery will start to wear out. You’ll notice that it doesn’t last quite so long between charges, a problem that just gets worse as more time passes. By 18 months or two years, you’ll be lucky to get half a day of run time.
Apple famously (make that infamously) engineers iPhones without a battery door, so you can’t just swap in a new power pack. However, you can indeed replace your iPhone’s battery, and it’s cheaper and easier than you might think.
In fact, I just put a new battery in my 15-month-old iPhone 4S, which was definitely showing signs of charge wear. Total cost: $8. Total time: 20 minutes.

— http://reviews.cnet.com/8301-19512_7-57565724-233/how-i-replaced-my-iphone-4s-battery-for-$8/