Hmm lets see. SWG is in like beta2 right now. They should start accepting a lot more people when they begin beta3.
I got into EVE beta - and although it looked really pretty, it was just so confusing and buggy, i couldn't figure out what to do.
Horizons is also taking beta apps now. I don't know when they plan to start it, but you can sign up.
EQ2 is far away, so don't even worry about that yet. And uhh, i can't think of anything else at the moment. I'll post again if I remember anything else.