If you want to sell it yourself, advertise it on 'autotrader.com' and 'cars.com'. Two really good sites to get your car in front of others.
If you just want to 'unload it', then if you have one near you, try a "Carmax". They'll give you a written offer that's good for something like 30 days and buy it from you on the spot. BUT your car either has to have a clear title (paid off) OR they will pay off who ever holds the title and give you a check for the difference.
Just a thought.....good luck!