Based on the information provided, it appears that you are trying to synchronize a Pocket PC style phone with Exchange 2000 Server. You cannot do this with Exchange 2000 Server alone, you also need Mobile Information Server. This dependency is done away with in Exchange Server 2003 and higher. Upgrading to Exchange Server 2003 is worth the effort in many ways but the current product is Exchange Server 2007. There is no direct upgrade path from Exchange 2000 Server to Exchange Server 2007. Making this switch will require a migration.