Speaking to Computer And Videogames, Crysis developers Crytek claimed in an interview that details on joining the multiplayer beta would be coming soon, presumably to the public.  While I blasted the limted standard-fare single-player demo that Crytek has been showing off at various media events, I could certainly see how some of the features might shine in multiplayer such as deflatable tires, demolishable buildings, and a number of interesting powerups.  Crytek's announced plans for detailed strategic team multiplayer sound very fun.

Expect more details on this as they become available.