There was a really simple game where you're just a smiley face chasing after other smiley faces in a maze, but it was multi-computer. Each person had his own view, and it was the simplest imaginable game. It was so much fun, though. We played it for hours and hours.
Sounds cool
Personally, I doubt PSP will have a phone built in. Why? Because of sonyericsson. As stated in the interview the PSP already has different connection methods, including wireless options. They will probably make it very easy to configure though, or even bring out an add on.