Free SEO Tools – use these free tools to help improve your search engine rankings. You can see where your competition ranks in the leading search sites such as Yahoo, Google and Bing. Plus you can submit your website to hundreds of sites completely free.
Simple Site Submission (Submit to 300 Search Engines and Directories), Free Whois Submission, Competitor Analysis (Spy on your competition and improve your rankings), Position Checker, Backlinks Checker.
These tools have very good descriptions of their benefits.