Swiffy converts Flash SWF files to HTML5, allowing you to reuse Flash content on devices without a Flash player (such as iPhones and iPads).
Swiffy currently supports a subset of SWF 8 and ActionScript 2.0, and the output works in all Webkit browsers such as Chrome and Mobile Safari. If possible, exporting your Flash animation as a SWF 5 file might give better results.
Flash is more than just video, however, and Flash games, interfaces, and other media types can't yet be replicated by HTML5. Still for content that Flash -- and its overhead -- aren't needed for, this sounds like a great tool. (It also sounds like something banner ad companies will jump on...)
I'm trying it out now on some simple Flash slideshow files but getting errors. If I get it working, I'll update with the results.