I know this was an old thread, but I'll say that I have bought a few guns from out of state on Armslist lately using Guntab.
I have no affiliation with them at all. When I first read about it I thought, bleep why hadnt anyone thought of that already? Its like Paypal, but for guns. The bummer is, even though now I have an account, the seller has to have one also. Though it doesnt cost anything for the seller.