Sign up is now, but it's hard to sign up. I can't get passed the first step. But anyways it is up for those interested in trying to get a spot.
http://www.blizzard.com/us/ (can't miss it on the left side of the screen)
Another thing that I found funny, a while ago some of us pointed out how Blizzard said they were releasing 3 seperate games and it seemed like a cash cow to milk the players... and we also wondered how they would do expansion sets...
well seems Blizzard rephrased their agenda and here it is:
TrilogyWhat is the StarCraft II Trilogy?
The StarCraft II Trilogy consists of the base StarCraft II game and two subsequent expansion sets. StarCraft II is subtitled Wings of Liberty (working title) and will include a lengthy single-player campaign that focuses on the terrans and puts players in the role of Jim Raynor, one of the series' main heroes. The first expansion set, Heart of the Swarm (working title), will follow later and include a single-player campaign focusing on the zerg and Kerrigan, Queen of Blades. The second expansion set, Legacy of the Void (working title), will continue the story experience with a single-player campaign centered on the protoss.
http://www.starcraft2.com/faq.xml#trilogy
It will be hilarious if the "expansion" sets cost as much as the original "main" game... when history says they should be around 20 dollars cheaper.