One of my favourite little Google tools is Google Browser Sync. It synchronizes all your Firefox state between multiple computers; cookies, passwords, bookmarks, etc. Very handy when switching computers.
Sadly the addon doesn't work with Firefox 3. And worryingly, there's been no update to the project since August 2006. It's a Labs project (ie: less supported than the usual) and there's been no hopeful response in this Google Groups thread. It may be time for an old-fashioned lobbying campaign, see also this blog post.