I would go to google and type in a search like (Xbox 360 your city, your state)
Even if no search results come up for your area, you are bound to see some Xbox 360 repair companies advertising on google.
Check out their sites and then do a google search for the name of the company.
If all else fails I would definetely check out ebay, but only deal with people that have good ratings.
Grab My Free Xbox 360 Repair Guide =>=>=>

Avoid the Xbox 360 Red Rings of Death - RROD
Related posts:

Call 1-800-4MY-XBOX for a repair service.