I believe no...I think online multiplayer is essentially tied into being console-specific.
360 vs 360 only
Ps3 vs Ps3 only
PC vs PC only
The Ps3 version of the new UT was supposed to allow Ps3 - PC matches but that's fallen through and will no longer be possible. I believe Mark Rein said it's in the works for the future (via update or patch) but not available immediately.