It's just a rumour, but it's one of those things that makes you go hmmm. From [link|http://www.macosrumors.com/|Mac OS Rumors]

Tuesday, February 3

Apple's 10.4 "Linux initiative" could work both ways. Today's crop of new reports on this topic not only provide considerable confirmation that Apple is indeed pondering a "Linux adoption" move, but hint at an angle we haven't covered yet.It has been suggested that Apple could gain quite a bit of attention and support from the GNU/Linux/OSS communities by porting more of its key pieces of software to Linux: Xcode, Rendezvous, QuickTime, iTunes, and iChat have all been mentioned. More on this later in the week as we continue to analyze this particularly tantalizing line of inquiry....