Mac OS X 10.3, aka Panther, will not be a 64-bit operating system, despite running on a 64-bit processor, the PowerPC 970 aka the G5.
Instead, the next major release of the Mac operating system will be a hybrid, much like version 10.2.7, codenamed ‘Smeagol’, which Apple has running on its pre-production Power Mac G5 machines and with which it will almost certainly ship production units.
If this is anything like the Carbon Finder Fiasco, we’re in for a good one.