Motion Playground has a Ski Stunt Simulator on their Games page. There’s a Java version that you can play online, trying out the ‘kicker jump’, ‘the wall’, ‘crash and burn’, ‘practice’. ‘Practice’ is good for just trying flips:
Those are my instructions above, so your mileage may vary. I recorded some videos of my antics; you can check them out below. The ‘kicker jump’ is my favorite, but ‘crash and burn’ really shows off how the pretty good physics engine can knock your skier around. I’ve gotten over ‘the wall’ and landed a couple of times now.
There are also videos of some of the jumps on the website, if you’re trying to figure out how to do them.
If you want even more, there’s a PC Version with a training section, better graphics and a lot more jumps, though many are still locked because it’s shareware.