Red's South has Glock lights, magazines (including the 33 rounders), and a pretty good collection of Glock pistols in 9mm, .40, and .45, including the SF models.
GT, if you are police / military, probably would be a good stop as well.
Cabela's usually has alot of the pistols, but pricing is really outrageous there. They probably have a few accessories, haven't really looked.
TexGuns is a smaller shop, and they generally don't have a wide selection of stuff for Glocks, but you never know what you might find going in there.
Thanks for the info, but I meant accessories only. I already have a Glock handgun.
I'm not looking for anything in particular, just getting a feel for the stores here.
Online places can be OK, but ordering a small plastic part can be murder on the wallet when they want outrageous shipping fees.