Discount Motorcycle Tires/Denver, CO/USA
 

This is a large shop, that sells a lot of tires 'online', also. Good prices and selection of tires, and they will mount them as you wait with no appointment!
They do provide some normal 'shop' services, but I haven't heard anything about the quality or range of the service.
This is a good shop to remember if you need tires when passing through the Rocky Mountain region. I haven't used them personally, but have had good reports from tourers, and locals.

http://www.discountmotorcycletire.com/Default.htm