I used Crossover Office and it will most likely have all the functionality there for Outlook (and MSOffice, Quicken, Media Player, and a host of other Windows apps). I LOVED this product, but don't really need or use it (for about a year now) but I'm sure its just gotten better. Oh yeah, tech support was pretty darn good too.... The only thing I couldn't get it todo was to sync my Palm with Outlook, but hey!

You know that you could also configure Mozilla as an IMAP email client. That way you get email and folders, but no contacts, todos, calendar, notes, etc... I do that if I need quick and dirty outlook access, or just use the webbrowser.