On the same day that Blizzard announced Diablo III is being pushed back to early 2012, Valve revealed that they want to get Dota 2 into the hands of players as quickly as possible. Valve originally planned to spend a year or so in beta as they added new features and heroes, but they came up with a new plan following positive feedback from players.
"Welcome to the new plan: We’re going to take the current version of Dota 2, which has The International set of heroes, and get it out there as fast as we can. We’ve still got some work to do in a couple of areas, so we’ll be keeping it invite-only for a (hopefully short) period of time. But there’ll be no restrictions on what players can do with it – they can release screenshots, make movies, shoutcast matches, write guides, publicly make fun of our HUD, or anything else their hearts desire. While they do that, we’ll be shipping regular updates with more heroes, new features we’ve been working on, and improvements on the existing content as we get more and more feedback."
If you're interested in playing Dota 2, head over to Steam to sign up for the beta.