All phone batteries run out.... but the iPhone battery sucks because when it dies one has to send it back to Apple to get it replaced at a price as well....
Well here is your chance to get it for $6.00 and that is shipped as well! Link is below..
1600mAh Replacement Battery Pack for Apple iPhone 3G
My iPhones batteries have not ran out yet but read and heard they only last about 18 months.... if your a gutsy person and your iPhone warranty has ran out and your a handy man or woman here is your chance to get a cheap battery.
PLEASE NOTE: Opening up your iPhone will void your warranty!
Repair Guide Below... Once you hit Step 10, just swap in the new battery and close everything up. That's really all there is to it.
Rapid Repair - iPhone 3G Take-Apart-Guide Repair by RapidRepair
If you don't care to take this on..... Rapid Repair (
http://www.rapidrepair.com/) can do the job.... in fact, they have a pretty nice deal: $39.99 buys you a "lifetime battery," meaning Rapid Repair will replace it for you every 12 months. You'll also have to pay a one-time installation fee of $29.99 and cover shipping costs. Still, it's way cheaper than a new iPhone--and a bum battery is a chief reason people buy replacements.