Google Browser Sync for Firefox

Google Browser Sync, free for download in beta from Google Labs, allows users to synchronize Firefox settings over multiple computers. Bookmarks, passwords, histories, and even persistent cookie preferences for specific sites are transferred, so that users don't have to spend time tediously adding them to each computer on which they use Firefox. Google Browser Sync can also "remember" which tabs and windows were open at last use, and "reopen" them when you open Firefox on another computer.