If they are honey bees, call Waid's
If they are not honey bees (wasps, hornets, etc) I've used Cozzarin's in Covert 387-5552.
I agree, if they are honeybees don't kill them. Seven dust WILL kill them all. Most honey guys will gladly remove them for FREE. Its very difficult to maintain a healthy hive now that the honeybees have been dying off in record numbers for an undetermined reason.
If they are'nt honeybees then Pat Cozzarin is excellent, or if you want to do it yourself get a bottle of that seven dust and spray it right into the nest or right at the extrance/exit. The wasps/hornets will track it in and it kills em all.