With just about every phone I have owned there have been plenty of threads that people moded their phone. Not so with the iphone. At first I was scared to attempt what I did but after I got so tired of having to charge the iphone all the time I took the plunge. What I did does void the warranty so IF you try this....... I have a 8gb 3G in black, I paid $189.00 so I did not have much to loose. - you take the phone apart all the way to the battery. - you remove the battery. - you (get ready) cut along the inside where the battery layed all the way through. This will allow the 2nd battery to lay on the 1st battery with the least bulk sticking out. - after the cut, smmoth away the edges with 180 grit sand paper (or finer grit). -order these 2 batteries form ebay http://cgi.ebay.com/NEW-SOLDERLESS-...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50 - cut the side contact that stick out from just one of the batteries (which will be the one that will sticking out a little. - solder the positive and negative to both of the batteries. - put everything back taking your time. - charge the iphone for at least 5-6 hours. -while the phone charges you can work on a case that you may have or that you have ordered for this mod. I ordered this one (or see pic below) http://cgi.ebay.com/MACALLY-METRO-W...|240:1318|301:1|293:1|294:50#ebayphotohosting - the plastic is not that thick as most cases. so I sanded off about 1-1/2 MM to accommodate the 2nd battery. With the back of the iphone case cut, that gave me about 1-1/2 or close to 2MM (Im guessing here) of room for the 2nd battery. With the case sanded and the phone charged I added the case to the iphone with the 3000Mah POWER and everthing fitted nicely. TWO batteries on the iphone with PLENT of juice to do whatever I need to do. At the end, my iphone does look just like the picture below. I do not have a camera handy but thats how it looks. I also posted a snap shot of what the iphone gives me as far as user use. I'm not much of a phone person but I do use the phone VERY heavy at all times. Lost of browsing, you tube, stream music via wifi, 3D games, you name it. In the 2 weeks that I have done this to this phone (did it to another iphone but not with the batteries from ebay) I have had absolutley no problems at all. Just like other phone I did this to everything runs like OEM. Accept I get awsome battery life. Anyways, thought I post this since I dont read much about iphone mods in forums so thought you might enjoy something different. Thanks for looking. EDIT: TO MENTION MY IPHONE IS JAILBROKED thats why you will see the number "29" showing battery power left.