One word of caution on Craigslist. It seems that the job postings are quickly becoming ways to obtain your info and then you get hit with spam really, really bad. Just proceed with caution.
There is another site I found yesterday that allows you to post free ads (if you post ads advertising your services) and then it "blasts" them out to 10 classified sites with the free version. To get an enhanced ad it's $9.99 and reportedly they blast out to over 3,000 free classified sites. I just tried yesterday so it's too soon to tell if it's helpful or not.