Nokia 6620 PC Suite
Nokia USA: Nokia 6620 PC Applications. I've had a boatload of trouble trying to get my contacts into my 6620. I know I have 5,400 contacts, so that is more than the average bear, but really. The original software CD has version 6.1 and it spend about an hour trying to synchronize and then would fail with an "Unknown" PC Sync error.
After much trial and error, I found the Nokia application page and downloaded 6.41, now it seems to work fine, although I notice that my Sony has trouble finding my 6620. It is supposed to autodiscover over Bluetooth, but that is unreliable.