Bummer! - Google Browser Sync will not be available for Firefox 3.0 !
Doing some Google on the subject I found that Google discontinued Google Browser Sync.
Evaluation process of a new solution:
1.) Chipmark - NO - no real bookmark integration - creates chipmarks - don't like it
2.) foxmarks - YES - currently using foxmarks. looks really good
3.) Mozilla Weave - todo
25 ways to sync your bookmarks
good comparison on wikipedia