Development will remain on the AVIARY_1_0_20040515_BRANCH (itself cut from the Mozilla 1.7 branch) until 1.0, with three releases candidates planned. The launch of Mozilla Firefox 1.0 for Windows and Linux is currently scheduled for Tuesday 14th September. The Mac OS X version will be released a little later, following additional work to make Firefox fit in the Aqua look and feel.
Bring it on. (I read on Mozillazine though that the release date is not likely to be accurate, and that Firefox may well be delayed. So I guess October? I just hope they don't rush it, getting as many bugs squashed as possible.)
With all the current round of exploits in IE6 and Windows being found, this browser can't come fast enough.