Firefox sync doesn't do the trick?
https://support.mozilla.org/en-US/kb/firefox-sync-take-your-...
It does in theory, but there have been some service problems of late (for a few weeks). I turned it off after growing tired of the error messages.
I figured I'd try out the latest Firefox and see if I can get it working before I definitively make the comment.
Thanks for the tip though. The machines I want to sync between are Windows 7 and Linux though, so no can do.