Recently EA announced that the open beta would start today (29th September), and guess what? It has! I’ve just started downloading it on my PS3 so if you want to have a crack before the game releases next month then get on board.
I’m not sure if it’s up on the 360 yet, but if it isn’t yet then it will be within the next few hours I would imagine. The open beta will allow you to play Rush mode on the Operation Metro map set in Paris. Rush mode is splits two teams into attackers and defenders, fighting over a number of strategic points on the map. If you want to see a little bit of the Metro map then check out this gameplay footage.
[Update: I've just been told that the Beta is also definitely live right now on Xbox 360, so go play it!]