I'm not sure what all programs do surround natively, but I've been playing around with the surround functions in Cubase.
Probably the most diffucilt thing to scrounge up for surround experiments is monitoring stuff. How do you balnce multiple speakers...'scuse me, monitors...without a 6 channel amp? Muliple amps or all powered speakers or...
I pretty much had to cobble together what I could. At the moment I just have a quadraphonic setup with my normal monitors augmented a normal stereo- fed by a stereo bus from an analog mixer. Its WELL worth the effort of hooking up just to get the idea of what to do with a surround system. Its a lot of fun, but now I'm seriously concidering saving up for a real surround monitoring system.
The process of going from your DAW to a 5.1 encoded file that can be put on a DVD is beyond me, still, though.
Take care,
Chris