For a week I thought I'd try an Apple keyboard on my PC with Ubuntu Linux and Windows XP, as I have just acquired one for free, it's not a new silver one though, but an old white one from 2005.
On Ubuntu 8.0.4 (and other Gnome using distros), it's easy to set up with the gnome keyboard tools (System → Preferences → Keyboard). Choose Apple under Models and add 'Apple United Kingdom' (or whatever your locale is) to the layouts. Also it is useful to select 'Press right control for third level chooser' under Layout Options, so you can access unusual keys like copyright symbols and double inverted commas etc. I set up F14, F15 and F16 as Previous, Play/Pause and Next track, but you can choose whatever you want them for in System → Preferences → Keyboard Shortcuts. I also set up F13 as Print Screen but I kept hitting it accidentally whilst aiming for backspace, so I set it to Alt + F13. Apple's help key is Insert, and the equals key is unassigned, and I gave up trying to assign it.
On Windows XP I had problems with the Apple keyboard. The volume keys worked straight away, perhaps because I had the Microsoft keyboard tools installed. I could set up F14, F15 and F16 for
Previous, Play/Pause and Next track but only with Winamp (with the RMX plugin which can also use joysticks and remotes) The eject key did not work straight away. To actually reassign keys its tricky, although possible with third party freeware. I tried Sharpkeys and Autohotkey but I almost messed up my Windows install using them. It was much more difficult to set up in Windows than in Linux.
On using it for awhile I liked using it with Ubuntu, the volume controls and eject shortcuts I like and the look of it, but I'm switching back to my Microsoft Comfort Curve 2000 as its much less strain on my fingers. Perhaps because it's old, the Apple keyboard needs more force to press the keys, and the key travel is too long. I hope the new Apple keyboard is better for the sake of Apple users, I now realise why a lot of Mac users use non-apple keyboards.
Update: Since then I've aquired a Powermac G4 which has the old Mac G3/4 keyboard with built in power button, I actually prefer this keyboard to the later one as it feels more comfortable!