For those people who are still using Fedora 6 (version 8 is the latest), its possible to upgrade Firefox from version 1.5 to 2.0. You can download Firefox from Mozilla, but its a gzipped file and its easier working with an RPM. Red Hat doesn’t provide an RPM for this version, but you can use yum for the installation with the following procedure.
Log in as root and use yum to install the program.
$ su root
$ yum --enablerepo=development install firefox