The best place is right here in the Classifieds section. If you follow the suggestions below you would certainly get more than you would from a pawn shop.
SUGGESTIONS:
1. Make an honest assessment of what the gun is really worth. Remember, it's not new and probably has a few flaws. Do a little on-line research comparisonsions. Some good places to look are auctionarms.com, gunbroker.com, galleryofguns.com, budsgunshop.com
2. Take some good quality pictures of the gun, with close-ups of the action, stock, and bore. Put two or three in the ad and have the others available to e-mail to interested parties.
3. Make sure your ad contains the make and model of the gun, its caliber/gauge, and a full description including any blemishes (is it stainless/blue/wood stock or synthetic/is the metal smooth with original finish, or worn, or pitted/is the stock chipped or scratched).
Place an honest ad with a reasonable price and it will sell fast.
the sportsman! You say you found a site called pawnit.com and your name is pawnitdotcom? Something doesnt add up here!