Looks like Firefox 6 will be released this Tuesday, according to Mozilla's wiki entry on its progress and final sign offs "Current Status: On Track with a few bugs still remaining. No concerns for Tuesday.".

The only outstanding bugs are:
- Bug 678470 - Update Firefox Desktop screenshots on Media Library
- Bug 677708 - Updates to the press kit for Firefox 6
- Bug 675967 - [Fx6Launch] IT www.mozilla.com support for Fx6 launch on 8/16

..and that last bug report shows the release date as this Tuesday! So get ready for another update.