Quick and Dirty Transparent Flash Videos II: From Flash to the Web
From Adrien-Luc Sanders, former About.com Guide
And that’s it; you’re done. You’ve just used Premiere combined with very basic Flash techniques that we’ve used in a number of ways before to perform a pretty complex function: converting a bluescreened movie file into a transparent Flash video overlay for the web. Try previewing it in your browser to see how it works, before making whatever tweaks are necessary to make it look just right on your page.