If you pre-ordered the Deluxe Edition of Red Orchestra 2: Heroes of Stalingrad, you can finally play the beta. This goes for anyone who has already purchased the game, and anyone who buys it before launch.
This first wave of beta testing will include three different game types and a variety of maps, so you will get a sample of the game's different aspects. You'll also be able to host your own server, meaning you can pick which maps you want to use and change the rules to your liking.
Up-to-date information on the status of the beta can be found on the Red Orchestra 2 Steam page.