Thunderbird Address Book/Android Contact Groups Synchronization
An Android app and a Thunderbird extension to exchange Address Book/Contacts Group data.
Current version of the app is available on Android market.
Read the help documentation here.
May 28, 2011: Thunderbird extension is Thunderbird 12 compatible.
The free Android app is here.
The Thunderbird extension is here (rename the file to end with .xpi to install to Thunderbird properly. Right-click the link to "Save Links As...", and change .zip to .xpi).
Yet Another Contact Manager
For Android 2.0+. Navigate Contacts and Groups with your finger, the trackball or D pad. Multiple accounts supported.
The app is here.
These apps are also available on the Google Play market.