Firefox 4 tentatively scheduled for a February release
There are now 160 hard blockers (serious bugs) left in Firefox 4, all of which need to be squashed before a release candidate can be released. Previous releases of Firefox have squashed about 100 hard blockers in six weeks, so February release is definitely going to be tight -- but here's hoping!
If you want to do your bit, and you're not a programmer, the best thing you can do is grab the latest version of Firefox 4 and take part in the test pilot studies. The latest beta of Firefox 4 really is quite good -- and if, by chance, you stumble across a bug, report it.