SimCity beta has now opened, EA and Maxis announced during their Gamescom press conference in Cologne, Germany. Or rather, it will be open as soon as the registration page goes live, which as of press time it has not.
Eventually though, prospective PC mayors can register for their chance to benevolently/malevolently control the lives of millions ahead of the game's February release window. No word yet on when the beta will actually take place, or whether Mac mayors will get to join in on the fun of not getting to sign up for a SimCity beta.
Update: The site is now live and accepting beta applications. Go get the key to your almost-guaranteed-to-be-obscenely-named city!