Since not long after the move to Intel chips - Apple have provided a utility called 'bootcamp' (it'll be built into the new version of OSX that releases this Friday ).

I got my first Mac ( a Macbook ) in May - and have been very happy with it. I installed bootcamp - which then let me install XP ( or Vista ) on a partition. It also provides you with a drivers CD which you run after installing XP/Vista to set up every bit of hardware on the system ( the camera, networking, sound, gfx, etc etc..all works beautifully - far better than the old Dell laptop I used to use ). There is an app in OSX and XP you can use to switch OS's on a restart - or you can simply hold down a key at bootup and a simple OSX / XP icon thing comes up and you pick which you want. It's great. I barely use XP now (apart from my desktop machine...which I'm using right now) - but it's usefull to have it there for the odd thing.

There are programs that let windows run in a window within OSX - but you won't get the same performance as you would running the OS natively.

As for running OSX on PC's..it's possible - I did it with a centrino based IBM laptop a year or so ago...but it's illegal - it's a breach of the OSX EULA as I understand it. It takes a bit of hacking/cracking to get the OS installed. Now that OSX is compiled for Intel machines- it works - but one of the reasons that Mac's work as well as they do is the integration between hardware and OS - Apple know exactly what the OS will be installed on. It's not quite as simple as writing software for a console (where every install is identical) - there are a few variations in components and thus driver requirements - BUT - Apple know everything that will be required and thus tailor OSX and the drivers to match that perfectly. A thousand different motherboards, a hundred different CPU's, a dozen different GFX cards, sound cards, etc etc - that's something XP / Vista has to deal with which OSX doesn't - and it's all the better for it.

Doug