Colorado School of Trades - Used to be the "name" school, but lately has deteriorated in the quality of instruction and graduates.
Montgomery College - Not only a good school ciriculum, but host to world class instruction through the NRA summer program. Take a look at the instructors, and you should be impressed.
Pine Tech - One of the very few that actually teachs CNC in their program. In my opinion their ciriculum is more oriented towards a production/factory job.
Trinidad College - An old and well established school, also host to the NRA summer program. In my opinion the day to day instructors lack some industry depth, but they have a good scholastic background.
Yavapai College - The only course of study to recognize that business sense is as important as working on guns for the guy who wants to start his own shop. The best place to learn engraving. But they actually have less hands on gun training than anywhere else.
Pennsylvania Gunsmithing School - Probably does more blackpowder work than the rest due to local interest, but a good school.
Lassen College - To me this is the best school still running. Course of study heavy into design and repair. Their summer program is also made up of world class talent. They offer more certifications than any other school.