Red Kawa has released a pair of freeware video converters to transcode your video files for use on PlayStation 3 and Wii. Both PS3 Video 9 and Wii Video 9 are based on PSP Video 9's GUI, with a number of key improvements. These applications can also be integrated with Videora to automatically create PS3- and Wii-compatible content from BitTorrent and RSS feeds.
As with Xbox 360, getting your PC's video files to run on PS3 and Wii is gonna be tedious -- so get started now. At least the good folks at Red Kawa are making the process free. (Of course, donations are always welcome.)