My experience so far has been excellent. I just sold the back wheel (sans cog and lockring) from my Fuji track for a quarter of what I paid for the bike. All the advice I got from bikeforums was to list high and see what I could get, and it couldn't have worked better. I got my asking within hours of posting the ad, with several buyers lined up as a backup.

So, don't be nervous about selling (unless you live in the middle of nowhere or in an area where you know the market can't support your hobby). Estimate what you think the bike is worth, then come up with how much money you would like to get for it, add the two numbers together and list.