The PSP2 - or, as it's being called temporarily, the Next Generation Portable - will as expected play nice with cellular data networks via a 3G connection. Here's what that means for your gaming.
Sony will be implementing a service alongside the new handheld called LiveArea, which in conjunction with an "app" called Near is able to detect at all times other PSP2 (or NGP) owners in your area. It'll show what people around you are playing, chat with NGP owners in the area, display rankings for games based on who's around, etc.
The picture above shows how LiveArea's user interface works, each "bubble" representing whatever a person in your vicinity is using.