Most Macs come with iLife pre-installed, which includes iMovie. iMovie can import pretty much any video format that will play in QuickTime player, but I don't think FLV is one of them. If you don't already have iMovie you can buy the whole iLife package for $80, or you can download the 30-day free trial of MediaEdit (http://www.miensoftware.com/Downloads.html ). There is no free software out there, though (at least not that I know of).