Mozilla is now indicating that we may see the launch of Firefox 4.0 next October or November. It has also reportedly updated its roadmap for the release of Firefox 3.6 and 3.7, with the former expected to debut later this year and the latter to arrive in the second quarter of next year. There are also reports that Fennec 1.0 -- the mobile version of Firefox -- will be made available at the same time as Firefox 3.6, and Fennec 2.0 with Firefox 4.0.
If the suspense is killing you, fear not; pre-release builds are available. Feel free to download Firefox 3.6 and 3.7 at your own risk.