The XNA team announced earlier today that a beta program's just begun for the "Community Games on LIVE" program. The bedroom coders amongst you will remember this service was announced back at GDC, and is aimed at getting user-generated games into the hands of 360 owners worldwide. If you're interested in trying out the service now (the full program's expected later in the year), they're still taking beta testers, so head on over and sign up.
Announcing: Community Games on Xbox LIVE Beta [XNA Team Blog]