10.6 for PowerPC?

[Caitlyn]

OS X 10.4 still runs on G3s. G5 to Intel is a somewhat bigger step.

I heard a rumor that 10.5 would be last PPC supported version of Mac OS X, but because of the reasons stated in the above quote, I personally think that 10.6 will be the last supported version of OS X.

 

[solvs]

I heard a rumor that 10.5 would be last PPC supported version of Mac OS X

It's just that. A rumor. At this point, we don't know, but since most of the Apple's users are PPC and they are still selling G4 and G5 systems today, I would suspect it will be awhile before Apple abandons it's PPC users. Otherwise, they would be shooting themselves in the foot as only those with newer systems would get to upgrade.