Roboform works. Go to their website and download the Firefox 3 version of the plugin.
Firefox 3 rules… soooooo much faster and so many fewer memory leaks (which was my problem since I always have about 10 tabs going).
All my plugins that I use work:
1. SEOQuake
2. Firebug
3. HTML Validator
4. SearchStatus
5. Roboform