I did this just yesterday with two Treo650s. I just installed the Palm software and chose to sync it with both outlook and palm desktop (the other is just palm desktop). After it was synched, I edited the contacts in Outlook to merge some entries, and get rid of duplicates, because she had SOME in outlok, and some on the Treo. Once everything was edited, I synched with BlackBerry Desktop. Everything came over perfectly.
If I may add to this string. I have two more complicating factors.
1. My Treo 650 is synced with Lotus notes - not Outlook and
2. I no longer have that application (company I left)
So - how do I get my data off my Treo 650 onto my Blackberry?