(Windows)
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/6.0/win32/en-US/Firefox%20Setup%206.0.exe
(Linux)
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/6.0/linux-i686/en-US/firefox-6.0.tar.bz2
(Linux-x64)
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/6.0/linux-x86_64/en-US/firefox-6.0.tar.bz2
(Mac)
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/6.0/mac/en-US/Firefox%206.0.dmg
(Other Languages)
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/6.0/win32/
(Others OS)
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/6.0/