This is showing up since yesterday 17th august 2011 16:00 pm (CET+1) on the Dota2 tournament page.
Things I know yet, the beta invites start after Gamescom (21th august)
GosuGamers got the confirmation the game won't be released before 2012
Tournament : http://dota2.com/tournaments/international/
( If possible, watch the tournament first prior to signup so you don't waste a beta key if you don't like the game )