Daniel B., CEO - Bezoka.com and Ungigs.com Hosting Solutions Optimized for: WordPress • Joomla • OpenCart • Moodle Data Centers in: Chicago (US), London (UK), Sydney (AU), Sofia (BG), Pori (FI) Email Daniel directly: ceo [at] bezoka.com
Dan has gave a very good link to searchenginewatch.com, alot of the SEO you can do on your own by reading material about it. There are several websites out there that will help you accomplish a great opt.
Directories are not worth it, the only ones that matter are dmoz, botw maybe, yahoo biz and msn, the rest just count as links and you are better off writing good content or encouraging your users to link to you or viral
It may sound too easy but why not google the term 'search engine optimiztion' and see who comes up in the top 10. Chances are that if they are in the top 10 they know what they are doing and can probably help you :-)