There is not a firm release date yet. Here is what cormyn said about this in one of the stickies in the AG3 forum:
We have a list of features that we are working on for launch, and when we write enough code for all of these features to be 100% working, we will consider the site "feature complete" and that's when we'll launch.
Since we're also working on other things, like maintaining AG2 and other side projects, we don't have a firm, fixed date for release.
Right now, we're aiming for a release date in the first half of 2011. That means it could be as far away as late June, but hopefully not. )
