I upgraded my Vaio (clean install) even though Sony "claims" my computer won't work with 7...it's really just to keep themselves from having to deal with customer support...
Here's the dealio...If there was anything specific that I needed to get working, I went to the MFG website (not Sony). However, I have yet to get any Sony specific stuff to work (funciton, s1, s2, eject) though I think that's more to do with my incompetence.
All that and all you wanted to hear was...Sony Vista drivers will work on Windows 7, and they will likely release "Windows 7" drivers eventually.