If you had some shred of hope that the StarCraft II beta would arrive this year after being delayed from this summer -- it's not happening. During a presentation at Russian games expo IgroMir, StarCraft II producer Chris Sigaty made it known that the game's multiplayer beta has been pushed back to 2010.
The first chapter (Wings of Liberty) of StarCraft II is now slated for release in the second quarter of next year -- between April and June, in other words. If that holds true, I suspect that the beta will arrive at some point in the first quarter, maybe even as early as January, though nothing is set in stone.
Blizzard first announced that StarCraft II would launch in the fall of this year, and beta sign-ups opened in May, but the company delayed the official release to polish the game as well as Battle.net, which is receiving a major overhaul.