Google explains the best uses of Flash for web sites

[mandy]

As many of you already know, Flash is inherently a visual medium, and Googlebot doesn't have eyes. Googlebot can typically read Flash files and extract the text and links in them, but the structure and context are missing. Moreover, textual contents are sometimes stored in Flash as graphics, and since Googlebot doesn't currently have the algorithmic eyes needed to read these graphics, these important keywords can be missed entirely. All of this means that even if your Flash content is in our index, it might be missing some text, content, or links. Worse, while Googlebot can understand some Flash files, not all Internet spiders can....

Try to use Flash only where it is needed. Many rich media sites such as Google's YouTube use Flash for rich media but rely on HTML for content and navigation. You can too, by limiting Flash to on-page accents and rich media, not content and navigation. In addition to making your site Googlebot-friendly, this makes you site accessible to a larger audience, including, for example, blind people using screen readers, users of old or non-standard browsers, and those on limited low-bandwidth connections such as on a cell phone or PDA. As a bonus, your visitors can use bookmarks effectively, and can email links to your pages to their friends....

Non-Flash Versions: A common way that we see Flash used is as a front page "splash screen" where the root URL of a website has a Flash intro that links to HTML content deeper into the site. In this case, make sure there is a regular HTML link on that front page to a non-Flash page where a user can navigate throughout your site without the need for Flash...

full article: http://googlewebmastercentral.blogspot.c...flash.html