I don't see any significant proof of this anywhere. It does make any sense for Apple to make the switch. Apple has really pushed developers to make OSX PPC apps. Now that that they've done this, they have to turn around and re-make Mac apps for an X86 processor?
Now, consider this....
What if Intel made a PPC chip? Rumors if true, are usually only partially true. In other words, they were correct, but didn't quite get the rumor 100% correct. So if Intel designed a PPC processor for Apple (and possibly Sony and Microsoft down the road for their video game boxes) then this wouldn't be so much of a problem.
I'm pretty damn sure that Apple has a version Mac OS X.3 and probably Mac OS X.4 for an x86 processor. They might just need cleaning up, but I'm they're already to go and could probably even ship within the next month or two if absolutely needed.
I still think this is purely a rumor, and one that most likely isn't true. But, never underestimate Steve Jobs if you piss him off.....