This page provides a link to skitown.com for the most comprehensive information on ski resorts across the US and Canada. Its a great over if you have a specific region in mind to explore.  However, be careful with the directions provided to the mountains because they will definitely get you close but sometimes miss a road or two near the end. Just click on the map where you are interested and select a resort.

Other helpful sites include:

Alpinezone.com – Great info on eastern resorts – simply click the ski tab
Heliskiguide.com – Snowcat and heli guide
Mountainresortguides.com – More great info on mountain resorts