I got lucky and my dad is a sucker (in the best way possible). My younger sister was graduating from college a month after I moved to the UK, so my dad bought the car from me with the intention of re-selling to her a month later. 1 year on and she still hasn't made a payment. I feel bad for my poor dad, but the rest of us saw that coming a mile away. I almost didn't let him buy it as I knew it would happen and hate that my younger sister gets away with everything....jealous sibling tirade over.
Before all this happened - I swear I didn't even ask him to do this - I was planning on putting it in some local papers and on some on-line sites. I think you have to pay for ads on most sites, but I figured in this day and age, it would get more veiwers than a newspaper.
I would also see if any local used car dealerships would buy it from you. They may not offer the most competitve price, but it will be sold and you don't have to stress about it close to your move date.