We use Maclink for converting common Winblows file formats like .doc (as used by Word) into something Mac applications can understand. It's a great utility, well worth having, and best of all it sits in the background on your Mac and kicks in automatically when it sees you opening a file it knows it will need to help you with.
By the way, further to what I was saying about Virtual PC, it's worth bearing in mind that it is not distributed by Connectix (its inventor) any more - it is now owned by none other than Microshaft itself. You can find out more about it at the Microsoft Mactopia webpage. Note that VPC version 7 is about to be launched, so don't go out and get v6 unless you can't afford to wait a few weeks.
Also bear in mind that when you buy VPC, you are buying two things: firstly a computer program that emulates a PC inside your Mac, and secondly a version of the Windows operating system. So, if you already have a legal copy of Windows, you can buy the cheapest version of VPC, which is the one that has the PC emulator programme but no Windows CD included, and load your own Windows CD onto it instead. You could save up to £100 that way, because you're not paying for another copy of Windows.
By the way, you can also load Linux or UNIX onto VPC, if you're in to that sort of thing.