EA and Maxis have launched an official SimCity server status page, showing the current condition of all regional servers.
At last glance the page wasn't actually working, but if you head over now it seems to be all go.
SimCity players, specifically in the U.S, have has much trouble accessing the game, so this page should give people an idea if their server is free or not.
Perhaps one of our biggest problems with SimCity is that if the server you started your game on is full, you can't access your same city from a different server. That seems like a rather large oversight to us. Apart from this issue though, SimCity is a fantastic game and we love it, as you can read in our review here.