I have founded a plug-in to play Flash Video (.flv) using QuickTime player. I have uploaded it to my iDisk public folder. Feel free to download and distribute it since it's free. If you have purchased QuickTime Pro, you can use the plug-in to play Flash Video and use the Save As... feature to convert FLV file into MOV file.
Of course, don't forget to install the Video Downloader plug-in for FireFox to download a web site's Flash Video file(s).