Details are emerging by the day. Here's the latest:
The following strings of code were uncovered in the 2.0 Beta firmware. They are not in the 1.x firmware and as such indicate possible upcoming iPhone superpowers:
"HeadphonesBT" and "RoleA2DP" -- Bluetooth stereo headsets for this release?"RoleRemote" -- Can the 3G iPhone serve as a remote for iTunes and/or AppleTV?"Printer" -- Does 3G iPhone now support direct printing?"BRICKED_AND_SIM_LOCKED_STRING" -- Ominous warning or just a bluff?
Others are saying the iPhone will be slightly thinner (by 2mm?) and that it will have GPS capabilities and support the Nike iPod Running thingy.