Couldn't find a list on their site, but they do have many countries across the world included. As for North America, here's the list (taken directly off the Satski app on my iPhone):
Canada:
Banff-Sunshine Village
Banff-Norquay
Big White
Castle Mountain
Cypress Mountain
Fernie
Kicking Horse
Lake Louise
Nakiska
Panorama
Revelstoke
Sun Peaks
Whistler Blackcomb
Mont Tremblant
Blue Mountain
Grouse Mountain
USA:
Alta
Arpahoe Basin
Arizona Sunbowl
Aspen - Buttermilk, Highlands, Aspen Mountain, Snowmass
Beaver Creek
Big Sky
Blue Marsh
Breckenridge
Brian Head
Burke Mountain
Canyons
Copper Mountain
Crested Butte
Crystal Mountain
Deer Valley
Gunstock
Heavenly
Hood Meadows
Jackson Hole
Keystone
Killington
Loveland
Mammoth
Marmot Basin
Moonlight Basin
Park City
Powder King
Red Mountain
Sante Fe
Smugglers Notch
Snowbasin
Snowbird
Snowshoe
Squaw
Steamboat
Stowe
Sun Valley
Sunday River
Telluride
Timberline
Vail
Winter Park
Yellowstone
Obviously many are missed, but that's their version of "large" resorts. If your mountain is on the list, it's well worth the small cost. I think Satski is very good. Mine are not on the list, but I bought it anyways in the hopes they would be (or added later). Alas, that's not the case. So I settled on Ski Tracks instead. Doesn't link to resorts, but it has most other features I want.
Hope that helps!
BTW, on the iphone, the App is officially called Satski 2.0. For some reason it shows up as "lite" but it is indeed the full (paid) version.