What it means:
You’ll want to buy a new Mac. Well, of course – but you _always_ want to buy a new Mac.
Update: But you won’t want to _wait_ to buy a new Mac. The new machines, when out, may or may not offer anything different from what the G4/G5 Macs offer – but why wait? If you need it, buy it, if you don’t need it, wait!
You’ll have to buy all new versions of your software. Yep, two years from now when the Intel Macs come out, if you want a new version of Office and Photoshop and whatever other commercial software you own, you’ll probably have to shell out upgrade fees for the new ones. All the more reason to move to (and create!) open source software!
What it doesn’t mean:
Existing Macs will be obsolete. No more so than any computer becomes “obsolete” the moment you buy it. The developer software “fat binaries” will allow programs to run on both platforms, and users most likely won’t know the difference. Sort of like Carbon and Cocoa now, but even more transparent.
Windows programs will work with OSX. Wrong. This should be obvious, but to many people it isn’t. Most recent software is written for the OS, not the chipset – tho a lot of software does have “hooks” that go down to the chipset level. Getting Windows software to work on it will still require an emulator (like Wine or VirtualPC). These emulators may get easier and faster, tho, which is always good news; and development efforts for Linux can be somewhat combined with those for OSX.
Update: There is some suggestion that Mac Intel hardware will be able to run Windows and OSX simultaneously. This sounds unlikely to me, tho the underlying software abstraction layer might make it possible. In any case, the new machines should be able to dual-boot to Linux or OSX. Oh, or that other atrocity, Windows. By the way, by the time those machines are released – Longhorn still won’t be available.
You’ll be able to run MacOS on any Intel PC. Nope. There will be new intel-based Macs made by Apple. They may have a toolbox chip (like the 68000 Macs did) or other unique hardware that OSX will refuse to run without. Of course, this hardware key may be subject to work-arounds, since Darwin (the core of OSX) runs fine on X86 hardware, now, for free. Notice though, that the Mac/Intel (Macintel?) developer kits include a special PC to run on. It does mean we’re a big step closer to this, though, so if Apple decided to become “just” an OS company and let Dell and Sony the Taiwanese battle over hardware, it wouldn’t be much of a stretch. I’d like to be able to run OSX on a tiny Sony laptop.
Update: There is some speculation, as well as blustering by Michael Dell, that we might see “the return of the clones”. Entirely possible, and if PC manufacturers want to licence MacOS, it would not be at all difficult for Apple to let them do this, if they want to. Will Apple want to? Time will tell.
Standard PC hardware peripherals will work with OSX. Not necessarily. Because the chip will be Intel, we assume the rest of the machine architecture will be Intel-style as well – and if so, then there will need to be software “drivers” for every periperhal, just as there are now on Windows and Unix. What a hassle. Drivers (or more importantly, the proprietary chips on hardware peripherals) should be standardized, especially in cases where the proprietary version does nothing above and beyond the standard.