With any Red Hat distro
yum install firefox
should work. What you need to do is to untar everything in /usr/local to create /usr/local/firefox-<x.x.x) then symlink to that directory to create /usr/local/firefox then create links to /usr/local/firefox/firefox (if you upgrade Firefox, you just need to change the symlink, not everyone's links) in the menu.
Personally, I'd use Yum - it's more integrated and will do everything for you.