Click for a map with some of the resorts on it (soon I'll have all of them, with good info)
here's the list:

• A-Basin » Summit County
• Aspen Highlands » Aspen, CO
• Aspen Mt. » Aspen, CO
• Beaver Creek » Eagle County
• Breckenridge » Breckenridge, CO
• Buttermilk » Aspen, CO
  
• Copper Mt. » Summit County
• Crested Bte. » Crested Butte/Gunnison, CO
• Durango » Durango, CO
• Eldora » Nederland, CO
• Howelsen » Steamboat Springs, CO
• Keystone » Keystone, CO
• Loveland » Loveland Pass
• Monarch » Monarch Pass
• Powderhorn » Mesa, CO (Grand Junction)
• Silverton Mtn » Silverton, CO
• Ski Cooper » Leadville, CO
• Snowmass » Aspen, CO
• Solvista » Granby, CO
• Steamboat » Steamboat Springs, CO
• Sunlight » Glenwood Springs, CO
• Telluride » Telluride, CO
• Vail » Vail, CO
• Winter Pk. » Winter Park, CO
• Wolf Crk. » Wolf Creek Pass
  

Until I can get a good picture up, here's the link to a good map on the Colorado Ski web site...