Ping, social bookmark, submit to RSS directories, post to blogs that are crawled frequently by spiders
Create & submit XML sitemap of your website into Google webmaster tool. You can also collect backlinks from high pr sites, it will also help you to get index your website
a "web 2.0" site is no different than getting any other site indexed. Link to it from as many sources as you can and submit a sitemap in webmaster tools.
As most others have already said start with blog commenting as well as forum posting. Be sure that you keep her for getting articles to ezinearticles as well as the different databases.