Eagle only has one bike shop, but it is a great shop run by great people.  The bike shop is located at 101 E. Second Street right on the corner of Second and Broadway.  Note, they are not open on Sundays, so make sure you have what you need by 4:00 pm on Sat.

http://mountainpedaler.com/

Note, as of Nov 1, they move into Winter hours of operation.