At this hour, there appear to be a few glitches in the various Firefox intro pages .... as Mozilla apparently is preparing to update the pages to formally announce the RC as well as make it more readily available.
The RC is posted to the Mozilla FTP server (and accessible at this time) and can be found here.
Update 2: Jan 11, 2010 5 AM ET: The full announcement (as well as pretty some significant improvements) can now be found on the Mozilla blog here.
Update 3: Jan 11 12 PM ET: Firefox users that have been testing Version 3.6 Beta 5 will be autodownloading the Release Candidate today and be prompted to update automatically. You can
check your progress by tapping 'Help' then 'Check for Updates' above the address bar.
Update 4: Jan 11 11 PM ET: The 'official' multi-language, multiple platform download page for Firefox Release Candidate 1 is now online here.
Update 5 - Jan 17 8 PM ET: Firefox RC2 has just been released and is delivering automatic updates to those running Firefox Beta 3.6 and Firefox RC2