ebay.com
seriously though.. ebay is the quickest way to sell a bike.
i have sold them on craigslist, but you get alot of no shows, and people who want to trade, and then youll have them low ball the shit out of you.
put it on ebay come spring, 5 day auction, boom your done.
you may not get as much on ebay as selling locally, but if you want a quick sale. thats the way to go.