There is a pretty good guide to ski areas that are accessible to NYC via buses and trains. Looks like trips are really cheap too - travel costs usually include greatly discounted lift passes. Perfect for all the tourists and residents in the city who don't have cars.
Check it out:
http://offmanhattan.com/2007/12/13/mini-guide-to-skiing-snowboarding/
Check it out:
http://offmanhattan.com/2007/12/13/mini-guide-to-skiing-snowboarding/