Yeah, the SE's don't see the content in your Flash files.
Using a "100%,*" frameset is the one method I see the most, and I've heard folks from various search engines even suggest this. You can put content on your frameset page in the NOFRAMES tag -- make it very representative of the Flash file content.
A few offsite text links with your principal keywords in the text will do a lot to help the cause. Even inner links in the site can help.
There's also the possibility we discussed back in Jan of using CSS to place text content off the page [webmasterworld.com]. I've heard no reports so far of anyone using this in practice and successfully boosting rank for a Flash page. If anyone does try it, I would suggest only representing the actual Flash content.
One last idea comes to mind -- do you have some kind of provision for people without the Flash Plugin? If so, how about making that page the index page, sniff for the plugin, and do a redirect for the Flash enabled browser to a opage with a different file name. Let your index.html page be straight vanilla.
Any other ideas anybody?