If you've the hybrid HD tuner, then Media Center should work. BUT it only works with the analog tuner. The digital tuner so far requires TCenter Pro. It's one of the worst software ever created using the .NET framework. I haven't been able to manually schedule a record since clicking on one of the buttons causes an unchecked exception in the .NET runtime. It also freezes often and has one of the ugliest OSD made in the 80s.
Short answer...not yet.
Note: I have the HD Card 800i (pci)