What seems strange to me is that they would switch to x86 now. Why didn't they switch before the G5 was made, when the performance of the fastest available Powermac was seriously lacking to Intel and AMD offerings. Currently the G5 keeps up pretty good with Intel and AMD pure on performance (not clock speed in the Intel case). We already know that IBM is working on the 970 MP, which should keep the G5+ on par with AMD and Intel offerings.
And with Freescale offering 2 GHZ+ dual core e600 processors later this year, or early next year, Apple should be able to get the powerbook/ibook and macmini up to date as well.
I really don't see any good reason to switch to Intel now. After all Intel seems to be stuck to 3.8 Ghz and AMD is gaining on them quickly with their more powerful dual core chips.
The switch to Intel could very well mean the end of Apple hardware, if OS-X runs on X86 and offers windows compatibility allowing viruses and adware to infiltrate our systems. Emulation of PPC software will likely create a slow and unstable platform. Also it will create customer confusion, when people with legacy G4/G5 systems can't run new OS-X software written for x86.
If this is all true, the apple future start to look really dark to me. It might just end up like the Amiga did, with only a very small group of dye hard users still supporting it long after the company died.