Making AJAX Applications Crawlable

Ajax: The Definitive Guide
This document outlines the steps that are necessary in order to make your AJAX application crawlable. Once you have fully understood each of these steps, it should not take you very long to actually make your application crawlable! However, you do need to understand each of the steps involved, so we recommend reading this guide in its entirety.
Briefly, the solution works as follows: the crawler finds a pretty AJAX URL (that is, a URL containing a #! hash fragment). It then requests the content for this URL from your server in a slightly modified form. Your web server returns the content in the form of an HTML snapshot, which is then processed by the crawler. The search results will show the original URL.

http://code.google.com/intl/sv-SE/web/ajaxcrawling/docs/getting-started.html