Cleo/Linux/Mac/Itunes lovers:
http://www.pcworld.com/news/article/0,aid,120114,00.asp
PyMusique (warning, site very overloaded)
http://fuware.nanocrew.net/pymusique/
DVD Jon hacked DVD encoding, hacked fairplay, hacked wmv9, and now itms. Apple fixed itms, released another version, he and his crew fix it -- its going to be a long battle. I can't help but think that Apple really could have released a Linux version and solved a lot of heartache.
But, who knows. DRM needs to be universally supported to be truely useful. Right now, RealNetworks is the only company that happens to have figured that out. Its just a shame HelixDRM isn't available to the public yet.