Attacking outlook is a little low guys... when you're working in a corporate environment, dealing with 200 - 300 emails daily (all of which you have to read) multiple calender invites, and need to associate files, sideshows, emails, other MS applications to meetings, journals and even basic notes; Outlook is pretty much the daddy out there. Whatever anyone says, Apple Mail, iCal and Address Book together really don't have the same functionality (although Entourage comes close)
Oh, and you've never used a REALLY bad mail client until you've tried Lotus Notes.
As for converting Outlook to Mail, Apple could have made it easy and they chose not to, because as usual they don't think anyone using a professional app on the PC would want to switch (they might be right). Microsoft are just as bad, because they don't help Entourage users either, but perhaps they have a motive for not making it easy.
The best way is to install Thunderbird on your PC, which converts Outlook effortlessly. Then save the MBOX file that Thunderbird creates and import it on your Mac. Veeeery easy...