I took piano lessons for a couple years when I was a kid. I never became a virtuoso, but maybe if I had had Piano Hero
I could have. It's an open source edutainer in the mold of Guitar Hero and the like, except with a piano instead of a guitar. It's a bit rough around the edges and definitely doesn't have the eye candy appeal of its console brethren, but if you want to improve your real piano skills (rather than your fake guitar skills), it might be right up your alley. Piano Hero works with any MIDI music file you throw at it, but currently it doesn't sync up to a MIDI keyboard--that feature will come with the 0.5.0 release promised later this month. Until then you'll just have to play along and pretend.
The Piano Hero web site seems to be sputtering a bit just now, but you can download the program for Windows from SourceForge