Basically, here's the scoop:
1) find a local FFL who does transfers, and ask him his fee to a) transfer and b)ship.
2) advertise gun in classifieds here, elsewhere, or on Gunbroker. State up front what you charge for shipping.
3) The buyer should have an FFL local to him ready to receive it, and this person will send his FFL copy for verification to yours. He will take care of that - it's part of what his fee is for. The legalities of transferring to the buyer are now going through the buyer's FFL and he will be responsible for the NICS check, legality in that location, etc.
An advantage of this is that an FFL can use the USPS. Most handguns, insured for full value, can go for $15. This is what my FFL charges. Skip the $75 and so FedEx and UPS overnight fees. Added to his $20 fee, it costs me $35 to ship a handgun anywhere domestic USPS priority mail can go.
The trick is having your FFL lined up ahead of time, and finding one who charges a reasonable fee. This way you know the costs up front and have a ready place to go to complete the transaction promptly once you get payment (paypal is a no-go - verboten - a USPS money order is a safe, secure way to do payment unless you are a vendor of some type with cc ability).
It's really not that big a deal - both Gunbroker and Auction Arms have lists of FFLs to do transfers by locality. Start searching there.
Also, both of those sights have tutorials about this stuff, so you can read more gory details there.
Tips on best success for selling: 1) Take LOTS of hi-res photos of all angles - as many as you have space to post 2) Describe everything, good and bad, in full detail. 3) State as much of the history as you know, good or bad. The full disclosure and thorough approach will increase the comfort of the bidders/buyer and induce them to pay fair/full price, vs. perhaps a better quality gun that is poorly photographed or described, or a lesser quality gun that is trying to hide something. Hide nothing and photos, photos, photos!