Review for Addressbooks Synchronizer by graham eddy
Rated 4 out of 5 stars
thunderbird 2.0.0.12, using webdav to own local server - works well, INCLUDING preserving distribution lists. have used it to populate newly installed desktops.
(would get a 10 if it updated at per-entry level instead of per-addressbook level)
To create your own collections, you must have a Mozilla Add-ons account.