Many web designers have have been using Flash and Ajax to improve the user experience on their sites, but, these technologies can make it very difficult (if not impossible) for search engines to index (or list) the site.
One of the main issues with Flash and Ajax is that search engines are great at following HTML links, but have a difficult time finding their way around sites which use Flash or JavaScript for navigation. While search engines are working to get past this issue, your best bet or creating a site that is indexable by search engines is to follow these guidelines:
1) Use HTML navigation
Avoid those JavaScript drop down menus and Flash based buttons, simple straight-forward navigation links work best. Spice them up with CSS and other web standards to create roll-over effects to enhance the user experience.
2) Text only links
Providing a secondary site navigation that is strictly text based goes a long way to ensure compatibility with search engines. These can be included on the bottom of pages and act as a mini site map for your site.
3) Add a site map
Create a page which is dedicated to linking to every page on your site, well at least those pages that you want indexed by the search engines.
4) Add an XML site map
An XML sitemap can be submitted to Google and other search engines to help them crawl your site better. These XML files can be created by services such as XML-Sitemaps.com and easily submitted to Google.
Follow these guidelines and see your website jump up the search engine listings.