A good example of a site that uses contests to stimulate traffic is the Texas Guaranteed Student Loan Corporation's award-winning Adventures in Education site. It is not free, but it's very inexpensive and allows you to easily submit to the top search engines and directories. I've used it with good results. Another way to improve your search engine positioning is to use a software program called WebPosition . Consider joining a reciprocal advertising exchange like LinkExchange .
Members display banners for one another's sites for free, maximizing everyone's exposure.
Check out VirtualPromote , another site with a lot of information about online promotion and how to get the word out about your website. Another site that gives ideas for self-promotion is Internet Resources for Online Promotions .