rivatuner works fine with 64bit vista. or, at least server 2008 64bit, which is essentially the same thing.
you dont need a program to use unsigned drivers, you just have to tell it not to look for them. its a command line prompt. google it, you'll find it.
i use rivatuner 2.09 by the way. no problems.
"nagasama no longer drinks tecate, or streaks out of the night for anything, and he has a fine wife so he has no use for your girlfriend...she is safe..."