Check out this care sheet:
http://www.deerfernfarms.com/Uromastyx_Care.htm
Make sure that you have a good set-up with proper temps before you receive your uro. Make every effort to get a captive bred animal. If you end up getting a wild caught (much cheaper and lots available) be prepared for a potentially difficult acclimation. With wild caught, you should also track down a herp vet before you get the lizard, and plan to schedule an appointment upon receipt to address parasite issues. Although the animal itself tends to be cheaper with wild caught, vet costs will quickly add up so in the long run captive bred is usually cheaper.
-Alice