There's people coaxing the PS2 version of Timesplitters 2 into playing online, via the same sorts of tunneling techniques that people have been using on the Xbox. Sometimes, even when you can get a game set up to work this way, they don't play all that well because they aren't optimized for this kind of connection. In the case of Timesplitters 2, it very nearly was online, the feature having been removed at the last second - perhaps as a result of that, I've heard nothing but good things about how it runs.
(CW)TB