To sync your MUSIC (videos, potos): in your phone, go to Main Menu > Settings > Connections > USB Setting and select Memory Card.
Plug your phone to the computer, and it will show up as 2.1gb file-system. Browse and upload/remove music and other media.
To retrieve and backup your contacts and SMS-messages, install Wammu from the Ubuntu software Centre.
Before starting the application, go again to Main Menu > Settings > Connections > USB Setting and now select Modem. Plug your phone into the PC.