there isn't a good one yet. the Moseley game works, but it's not really like skiing.
my prediction: it's gonna be a year or two before we see any decent ones.
MTB-related video games share the same gaping hole -- can't find a decent one, although Downhill Domination
gets pretty close to simulating a tough technical DH run. Other than that, only BMX games bring something worthwhile to the gamer.
I guess snowboarding games are the only outlet for snowsliding video gamers. I saw a new one at my friends' house, it was called Amped 2
and it was very cool and very much like actual snowsliding in its feel and sensations.