Trade-a-Plane is a good place to start. Most every airport I've ever been around has at least a copy somewhere. Or, you can subscribe on line for a couple dollars a month.
Also, check out
www.controller.com and
www.aso.com . Both are free to browse.
Having said that...
I advertised my 182 in all three of those publications/sites... the only responses I ever got was from the Trade-a-plane ad. There are more airplanes listed there, and you can search by geographic area also.
A few others;
www.barnstormers.com isn't bad, they've cleaned it up in the last year or so. Aero-trader online is another place.
... and e-bay if I could go look at the airplane before bidding... but that would be a last resort.
I secured my financing through AOPA, no hassales and it was a painless deal. All that was required to fund the loan was a couple signitures, a copy of the bill of sale (FAA form 8050-2), and a signed purchase agreement (that we made up on the FBO counter).
