Jason is correct. You can send the entire phonebook at once on a Treo 650 by setting the category at "All" and choosing "Send Category" from the Treo menu.
But be aware that if you have contacts with multiple phone numbers (Home, Office, Cell, Fax) in your Treo phonebook, the Z1 will create a separate contact for each phone number. The Z1 will label all of these the same (i.e. "John Smith"). You will then have to manually change the label on the Z1. Since the Z1 only allows 400 contacts, you will run out of storage space after 100-150 contacts if they in fact have multiple phone numbe
