Here are the official FTP links for downloading Firefox 10:
For Windows (15.1 MB):
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/10.0/win32/en-US/Firefox%20Setup%2010.0.exe
For Mac (31.4 MB):
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/10.0/mac/en-US/Firefox%2010.0.dmg
For Linux (18 MB):
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/10.0/linux-x86_64/en-US/firefox-10.0.tar.bz2
Hope this helps
For Windows (15.1 MB):
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/10.0/win32/en-US/Firefox%20Setup%2010.0.exe
For Mac (31.4 MB):
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/10.0/mac/en-US/Firefox%2010.0.dmg
For Linux (18 MB):
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/10.0/linux-x86_64/en-US/firefox-10.0.tar.bz2
Hope this helps