Later this year, Openfeint enable real-time multiplayer gameplay and VOIP between iOS and Android devices!
There will be lobbies and matchmaking for normal titles. Titles like an FPS will have team based voice chat and 16 player game servers.
The other good news is that the basic PlayTime will only take about a day for devs to incorporate it.
Personally, I'm excited for this since OF is also planning on supporting GameCenter on iOS so devs really get the best of both!