Okay, I am also looking at a GL2 for next years ski season. Here's what I've found out based on my research...
The Gl1 and the Gl2 are essentially the same camera. It will be slightly harder to get your hands on a GL1 due to the fact that they are discontinued by Canon (replaced by the GL2). However, if your on a tight budget, and can find a GL1 for a few hundred less (they will probably be VERY close in prices anyways..) then go for it.
Now, I've heard that the GL2 does a really good job on low light situations. Apparently, there is a comparable Sony model (Vx2000???) that preforms much better in low light than GL2. But, the GL2 still does a really good job.
It has a built in optical image stabalizer which should definently come in hand for follow cams and that sort of thing. The lens is amazing which is understandble because Canon Optics have always been incredible. And, the image quality is pretty incredible as well.
All in all, it's an amazing camera for action sports in general. You'll see tons of people in skiiing, snowboarding, and skating movies filming with the GL2(1).
(This is all based on what i've read, and what i've heard from people who use the camera. I personally don't own one...yet ;)