Yup, the lovely media... Neither Apple, IBM, or Intel have confimed this. No article mentions specifically how this information was "learned".
I'm not so sure this is about Apple computer line. I've heard that the Ipod uses Intel chips. Could be for some new media device from Apple or even a chipset. Guess we'll know Monday. There are always big rumours months before Apple keynote speaches. I think they enjoy watching all the activity it causes. Not to mention the free plublicity it generates.
If Apple did change their Macs over to Intel x86 CPU, I see three possibilities: Apple goes under as they have just betraied their userbase, PPC development slows as IBM looses a major customer, or both.
It's most likely not what all the talk is about, though I bet Apple is loving every minute of it. Look at it, everyone is talking about PPC vs x86, Mac vs. Wintel PC, etc. in an attempt to rationalize their own logical conclusion of this rumour reported as fact. It's saving Apple million is advertising. Sure their stock will got wonky, but after the show when all is known it'll skyrocket.