Start here on "The Swap Meet" section, then the MTFCA classifieds & the HCCA classifieds. All are free ads, the HCCA will charge for pictures.
A good description, realistic price & pictures will sell the car quickly. It is a good idea to state where it is & if you have any shipping contacts.
The easier you can make it for the buyer, the more energy he will have left to write a check.