According to this ZDNet article Apple will announce tomorrow their plans to dump IBM’s PowerPC processor in favor of Intel’s x86 based processors.

Apple has used IBM’s PowerPC processors since 1994, but will begin a phased transition to Intel’s chips, sources familiar with the situation said. Apple plans to move lower-end computers such as the Mac Mini to Intel chips in mid-2006 and higher-end models such as the Power Mac in mid-2007, sources said.

The announcement is expected Monday at Apple’s Worldwide Developer Conference in San Francisco, at which Chief Executive Steve Jobs is giving the keynote speech. The conference would be an appropriate venue: Changing the chips would require programmers to rewrite their software to take full advantage of the new processor.

The Wall Street Journal reported last month that Apple was considering switching to Intel, but many analysts were skeptical citing the difficulty and risk to Apple.

That skepticism remains. “If they actually do that, I will be surprised, amazed and concerned,” said Insight 64 analyst Nathan Brookwood. “I don’t know that Apple’s market share can survive another architecture shift. Every time they do this, they lose more customers” and more software partners, he said.

Apple successfully navigated a switch in the 1990s from Motorola’s 680×0 line of processors to the Power line jointly made by Motorola and IBM. That switch also required software to be revamped to take advantage of the new processors’ performance, but emulation software permitted older programs to run on the new machines. (Motorola spinoff Freescale currently makes PowerPC processors for Apple notebooks and the Mac Mini.)

It’ll be interesting to see how this plays out in the long run if it does come to pass. Presumably if Apple wanted to they could sell their OS on it’s own to PC users looking to move away from Windows who aren’t keen on Linux, but considering the markup Apple has traditionally put on their hardware it’s hard to imagine they’d want to offer the OS by itself even if it meant snagging a larger market share.