Google Contacts is a add-on for popular email client Thunderbird that allows to sync Gmail contacts with Thunderbird. This is a quite useful addon if you use both Gmail and Thunderbird, i for one who uses both of them.
Download the addon and save it to disk, now open Thunderbird and go to Tools > Addons and install Google Contacts. It will ask you to enter number to download contacts, if you have hundreds of contact it may not download at once. It can detect the Gmail contacts already setup in Thunderbird. [Via Lifehacker]