Apple already has an x86 version of OS X running internally. According to reports, they are using this fact to keep pressure on Motorola. Motorola's efforts have been too slow. The likely alternative, however, are IBM 64 bit Power4 server chips, which are apparently being modified to accomodate Altivec vector processing. IBM has to license this technology from Motorola, and that was a point of contention which I believe has already been worked out - according to reports. I'm not sure what this means for Apple and Apple's users, but I think it could be quite good.
Apple switching to x86 architecture is really not a good thing in my mind. It complicates things immensely for Apple and for Apple users. It's only good for people who already bought an intel pc who want a free ride and a better OS. I have no sympathy. A lot of great software would have to be modified to run on x86, and classic/carbon apps might be the biggest problem. I would not, and I'm sure 95% of all users would not want to deal with that and other issues that would likely arise. In addition, contrary to some on this site - I'm not one of those who believes the whole Mhz hype. My computer does much better at half the mhz than most of my friend's pcs with much higher mhz. It's like rpms, having an engine that runs at higher rpms isn't necessarily an indication of efficiency. I know people who do genetic and other work on Macs, and Macs crush Intel pcs.
However, if Apple wants to introduce a SERVER on x86 architecture, I don't see a problem with that. That makes a lot of sense to me.