I'm just looking into to putting something together now, having jumped on the 4e boat yesterday. I'm going to play around with Kloogewerks (kloogeinc.com) a little and see how well I can get a game definition and character sheet working.
I'm going to be playing in a campaign going up when the DDI VGT goes live, but I want to run my own offloading some mechanics onto the PC. Klooge is also written in Java, which is a bonus for getting players.
If things go well, I should get into my preferred mode of DMing one game over VGT, playing in a face-to-face game and playing in a virtual game.