There is a thread going in Google Groups about Flash and Getting Indexed. This discussion focuses on techniques for providing search engines an HTML text file to chew on instead of trying to parse the flash itself.
Deepa was concerned that this might be seen as a spammy duplicate content technique by the search engines. The consensus in the discussion was that this was in fact good behavior, provided that the text content matches up with the content of the flash.
Of course, the trick part is that it’s not completely natural for the text content to line up exactly with the content of a movie. They are different mediums that benefit from different treatment. So there is going to be some variance in the content due to that simple fact.
Perhaps the thing to do, if you insist on having Flash on your site, is to write an HTML page about the same topic as the Flash, and target that page at users who do not have the ability to view Flash. Write the page as if you were trying to accomplish the exact same things as you are doing with the movie.
The words may differ some, but the intent would be exactly the same.