July is nearing an end and we will have a new major version of Firefox by the end of this month: Firefox 6. It's in Beta 3 right now and i believe they will just release one RC and marked it as a final release or probably just skip it and directly goes to final release, depends on the situation.
Anyways, i personally don't really like the idea of Mozilla new release cycle. It would make a burden for the vendors to maintain the applications, as there are no separation between a security update and a maintenance update. With the new release cycle, both are incorporated and new version will come up in the next three months or so. I prefer the old one actually.