Are all of the components original to the bike? How many miles are on it and is the frame in good shape? I would get a basic tune up but not repkace the tires unless they're im really bad shape. I also would only sell it locally. This a steel commuter, right? I don't know that I'd expect to get much for it and, frankly, if it were me, I'd just hold onto it as a back up bike.
Ask yourself how much you'd be willing to spend on a 8 year old bike when there are lots of new bikes to be had in the market. IMO, the best thing the bike has going for it is that it's steel, but I'm not the average used commuter buyer will appreciate that.
But that's the nice thing about Craigslist. It's free. If you don't get a nibble after a couple of weeks, drop the price.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher