The SimCity beta will be from January 25 to January 28, and registration is underway now on the game's official page, the SimCity Twitter feed said this morning. Here's the tutorial level.
UPDATE: It looks like the video has since been taken down. Sorry folks.
Perhaps not coincidentally, that video above showed up on YouTube around the same time. It showcases the game's opening tutorial.
The tweet said that beta users will get to play an hour-long slice of the game. It's a closed beta, with no word on how many registrations they're accepting. Players may replay the hourlong chunk as many times as they want during the four days. It's PC only, no Mac.
SimCity Beta [SimCity]