This is still very much a rumor and speculation at this point, but with WWDC just around the corner, you would more or less expect it. According to the folks at Apple >Cellphones. Read more about AT&T, iPhone, iPhone 4, launch and wwdc.
|Key Specs||iPhone 4|
|Max. Total Storage Capacity||32 GB|
|Battery Capacity (mAh)||1420 mAh|
|Complete product data||Apple iPhone 4 Full specs|