The Atari Beta Testing Website (thanks Shacknews) has word that they are accepting applicants for closed testing of the upcoming free MP add-on for Unreal 2:

Also, the Unreal 2 Expanded Multi-Player free expansion is up and taking requests for the closed beta. This multiplayer mode is a class-based team game where players fight for control of artifacts and energy using a deadly arsenal of weaponry, vehicles, and defenses. If you would like to participate in this beta test, please register for an account in Atari's beta testing system and request to be a part of this exciting project.