Details on the 3G iPhone are still very sketchy, although Steve Jobs is expected to anounce it at the WWDC Keynote. Obviously it will be 3G but that is all that has been confirmed, it may have GPS, it may have a slightly better camera, although don't expect a 5MP. It will also be running the latest firmware - 2.0.0
The form is expected to be very slightly smaller, but deeper and more of a curve on the back rather than flat, it is also expected to be available with coloured plastic (MacBook style) in wither black or white.
As for availability over here, I have been told that Movistar will have it within the month, I expect it to be in the region of 400€ with a 18month or 2 yr contract.
Thats about it for now though....