Dan,
You really don't move it.
What you do is on the "new" DC, where you want a GC, open
AD Sites and Services
Expand your site - probably Default-First-Site-Name
Expand Servers
Choose the server for the new GC location
Expand it and expand the NTDS settings
Go to properties and click on the GC box.
After your DNS updates, you will ave a GC on the "other" DC.
If you want the "old" one to be gone, just do the same as above but clear
the check box.
BE SURE TO WAIT FOR REPLICATION and DNS updating
Ed