Mozilla Released Release Candidate (RC) 1 of Firefox 3.6 late Friday afternoon. From the Welcome Page:

This latest update contains the final set of changes to be included in Firefox 3.6. Please help us test this release candidate.

• Select a new persona from the Personas Gallery.
• If you find a crash, please report it!
• More than 75% of Add-ons work. Test your favorites!
• Try watching a video in full screen mode.
• Have you seen websites using WOFF fonts?
• Kick the tires with improved JavaScript performance, browser responsiveness, and startup time.
• See the release notes for more details.

Current Firefox 3.6 Beta users can upgrade via the Check for Updates option in the Help Menu.