Ok, here's my two cents worth.

When the "spiders" crawl a website, they follow the links. So if you have a new website with no incoming links you can try this.

Find forums related to your site that are indexed by the search engines. Sign up with them and be sure to add a signature including your url. When the spiders crawl, they find your link and follow it to your site. Bingo! You are indexed.

This doesn't mean you get top billing or even in the top gazillion pages. That's a whole other story. But one clue, the more links the more threads the spiders have to crawl.