I emailed myself my address book from my Treo as vcard, and tried to import into Outlook Express. It didn't like some of the entries, so I imported it into Evolution (on Linux.. Windows version available), and re-exported it. Then Outlook Express liked all the entries, so I imported it, and synced with my Pearl.
I helped a person set up his Plam desktop to sync with Outlook. We had to use the origianl CD to apply the conduit. After syncing with Outlook it was then easy to move all the contact info to the Blackberry.