Back to the OP question. If you want it to sell faster I have found Craigs List to work well at selling electronics and usually very quickly. Give that a shot too.
I usually go buy a new iPhone the day it comes out, then sell the old one on eBay...as other posters have said, eBay or Craigslist are always good choices.
Put it in the marketplace here as well, that's what I did with my iPad I sold. I am going to order a 64GB iTouch, yeah I said it, I want to keep my ever growing game collection on my iTouch instead of my iPhone. Some of these games are 500+MB each.