Okay, first off if the seller happens to in your state and reachable, ya can do a face to face private sale no paperwork involved.
If weapon is outta state, ya must first find yourself a local firearms dealer, sporting good shop or gunshop in your city. Go visit them and find out "How much they charge to do a firearms transfer, most reasonable [b]F[/b]ederal [b]F[/b]irearms [b]L[/b]icensed dealers will charge ya 15-25 bucks to transfer the weapon to you... if they want too much, find one that's more reasonable to deal with...
Once this is done go to the EE and find a rifle, pistol or shotgun..... make a deal, then go to the FFL dealer/shop ya picked and ask them for a 'signed" copy of their license, which they will give ya....send this and payment by USPS or whatever to the seller, he in-turn will box up item and ship it to the FFL dealer/shop ya chose, dealer calls ya, tells ya rifle is in, ya go down fill out a form 4433 and go thru NICS or show your CHL/CCW permit and pay him his fee for legally transfering rifle into your name.
FWIW, this can be done legally in most states NOT as a dealer to dealer transaction, (but w/ the wacky laws nowdays check to be sure, as some state laws may require it) but as a private person in one state, legally transfering the weapon THRU a dealer (which must be done to be legal) in another state, then into your possesion.
That's it, btw, ya can go to [url]www.gunsamerica.com[/url] and I think they have a list of FFL dealers by zip-code for your area...
Mike