Version 0.3 allows synchronizing one account with several address books, supports synchronizing an address book with only one group of your choice, and can import contacts from Facebook, Plaxo, Twitter, and MySpace. 0.3 also synchronizes contact photos and birthdays.
Version 0.4 will merge contacts during the first sync which should prevent duplicates. You should start from a new address book when you start to sync; gContactSync will pull your contacts from Google.
If you find a bug or have a question, please let me know about it. See the support information for the details.
Note: Mailing Lists in Thunderbird in Seamonkey are still somewhat buggy, especially when contacts are dragged and dropped into them. They don't work with contacts that don't have e-mail addresses, so gContactSync will add e-mail addresses like email@example.com.
If you are interested in browsing the source or using the very latest version of this add-on its CVS repository may be found here: http://gcontactsync.mozdev.org/source.html
Please read the FAQs before posting a review http://www.pirules.org/addons/gcontactsync/faq.php