The best way to get the money for them is to rent a table at a gun show and sell them yourself (assuming it's legal for a non-FFL to do that in your state). The second-best way is to sell them via the online auctions/sales sites. Third is to put them on consignment at your local FFL (he gets a percentage of the sale price). Last would be to sell them to a dealer, who will give you the lowest price.
Anyway, the way to get the most people interested is to have an information "card" (or whatever) to go with each gun, giving as much detail as possible, as well as a price. Information about the gun is often as important as the gun itself to buyers.
If you are selling online, you MUST have good-quality pictures. Buy or borrow a digital camera, and MOST IMPORTANTLY, buy a couple of cheap clamp-on lights so you can light your guns for the pictures. The lights should be on the left and right so they cancel the shadows. Very bright is good.
Use white butcher paper for the background (it looks better, hides your messy garage/table/whatever, and there are no distractions in the pics). Take a "group photo" of the gun with all accessories visible, then take detail pictures of anything important (especially damage/wear/flaws). People appreciate the honesty, and you won't have people trying to return things, etc.
Be friendly and ready to answer any questions. Give people the benefit of the doubt, but make sure you're covered too. If something goes wrong, you want to give the person a chance to fix it, but you also want to have enough VERIFIED info so you don't get ripped off.
Know that if you price low, you'll move the items faster. Higher prices will get lots of "fondlers" but fewer buyers. Learn what things are SELLING for (which isn't always what people are ASKING for), and price your items accordingly, adjusting for condition.
Good luck.
-Troy