I just read at http://www.osnews.com/story.php?news_id=15025
is making a world wide beta test of SuSE Linux Enterprise Desktop which
made me wonder: how much trouble would it be to port it to PPC. The next
version of OS X is rumored to be Intel only, so there will be millions
of machines with an OS not developed any more. These are pretty well
built machines, so they will be around for another 3-4 years.