Currently, my Performa 6300CD runs Debian Woody (3.0). Would it be possible to upgrade it to Lenny? Would it require a newer kernel? There's one on the nubus powermac sourceforge site that's 2.6.31 but i have yet to test how well it works.
Yes, you would need to use a 2.6 kernel in order to use Debian Lenny. But the Nubus 2.6 is still in development and not that stable yet. So how well it will work (if at all) will vary. However they've currently been focusing on the Performa platforms, guess you'll have to test and see.