Sometimes the media draws an inference from a rumor and the story gains a life of its own, regardless of how based in truth it is. I may be as wrong as can be on this one, but there's no way I can see Mac OS is going to Intel any time soon.

Here's the latest rendition of this rumor, as told by the Macworld Weekly newsletter:
... Bear Sterns analyst Andrew Neff released "PC Manifesto," a report on the state of the personal computing industry that predicted, among other things, that Apple would likely make a switch of its own from chip suppliers IBM and Motorola to their rival Intel. The reason? Intel can provide more than twice current processor speed, and that will likely win new customers. A second analyst-heavy feature from the NewsFactor Network posits that a Microsoft/Apple showdown for dominance of the desktop is coming.

Why do people think this? Here's a quote from a ZDNet article entitled Intel inside a Mac? Just wait.
Since Mac OS X is built atop a version of Unix, porting it over to Intel processors is fairly straightforward.

There's a huge problem here. The part of Mac OS X that's UNIX is most certainly easy to port. Try "done". You can get it here today if you wanted to. The problem is all you'd get is a command line. That's right -- a terminal. Like a DOS window. Woohoo. Not a single OS X configuration GUI, not the widgets that the GUIs would be made from, not the libraries every good Cocoa programmer uses, nothing. Just neat, "headless" UNIX apps like Apache, vi, and grep.

At the same time, most of Apple's serious software, and even much of its iApp apps, like iDVD and iMovie, are optimized heavily for the Altivec instruction set. I'm no assembly/computer language wiz, but here's what I do know [if I believe all I'm told]. There are certain instructions that can be called inside of the G4 processor that help with digital video processing. These instructions are not in the x86 platform (Intel and AMD, and Transmeta, to a certain degree, for all that matters). Rewriting these apps would mean losing the hardware advantage, that is, the advantages from these special instructions, Macintosh has had with apps like Photoshop. Unless the G4 really is quite a bit slower than a comparable Intel or AMD model, these niche-specific speed gains will go out of the window and "normal" apps, Microsoft Office, etc, would tank if Apple changed platforms.

So here's the bottom line. For Apple to use Intel processors, not only would they have to start thinking of ways to port over the "Apple-specific" parts of OS X (I'm guessing that's non-trivial), they'd also have to figure out a way to combat the Macintosh operating system's possible speed losses to Windows in not only everyday apps but the applications where Apple used to shine.

Add to this that IBM has a new PowerPC chip where it'd be easy to migrate existing Mac OS apps, and I think you have a pretty good case against expecting a move by Apple to x86.

That said, if Apple was going to move, now's the time. I've never tried Darwin on x86 hardware, but if they've bothered to keep it robust "cross-harware", there has to be a reason (though most likely just because it's smart and relatively easy to do with the pretty plain jane OS). More importantly, if Cocoa really builds off of Darwin directly and can be compiled against it (created without anything new added), this port might really be incredibly easy. And there's nothing Apple would rather have than people having to chunk OS 9 and have to buy new software for OS X. More software buyers mean more money in the Mac market means more software developers see the Mac as viable. That means more hardware sales for Apple.

But, again, I can't and don't see it. It'd take too much time for the rewrite and too much niche-specific speed would be lost. If this was Apple's plan, they would have done this while rewriting OS X, and we would have heard more about this possible switch than one comment from Steve Jobs flung into the ether. Unless I'm wrong and Cocoa works atop x86 Darwin just as easily as PowerPC, and possibly even then, I just don't see a switch happening.