American Aviation in SLC has an ATC810 sim and they do an excellent prep course. It's about 30 mins and usually costs around $50. But beware, they book up fast so make sure you call either right after you set up you interview date or if you're more flexible when they give you your date opinions, call and ask the availability of the sim and use that info to help set your date.

AA is located behind the Candlewood Suites and can easily be reached on foot from almost all the airport hotels.

http://www.americanaviationwest.com/about_us.htm