for starters, use the meta description field in the header. Google uses that as the default description for the site when it displays its results.
while there isn't a <noflash> HTML tag, best practice is to also provide a non-flash version of the site. The best way to do this to put all the text you want google to see on the index page. Then at the top of that page, put a one frame flash movie that has an action that forwards the user to another page (like, index2). On that next page, post the flash version of the website.
so google will index the text version of the index page. when a user clicks on googles link to the index page, if they have flash installed in their browser they will instantly beforward to index2 and view the flash movie of the site.