I unistalled firefox 3.6.9 $ yum erase firefox

Extract firefox-6.0.2.bz2 in /opt (with root) $ cd /opt $ tar xvf firefox-6.0.2.tar.bz2

make a link /usr/bin/firefox -> /opt/firefox/firefox (with root) $ ln -s /opt/firefox/firefox /usr/bin/firefox

for convenience, you may need to edit or create a launcher in the launch bar.

Note that I cannot watch flash videos with firefox 6, no plugin available, looking for a solution right now

Here is the fix that helped me upgrade to Firefox 10.0.2 on CentOS 6.2 (refer to http://www.if-not-true-then-false.com.../install-firefox-on-fedora-centos-red-hat-rhel/ this link).

1.Backup your current Firefox 3/4/5/6/7/8 profiles (just in case):

tar -cvzf $HOME/mozilla-firefox-profiles-backup.tar.gz $HOME/.mozilla/firefox/

2. Change root user:

su -

3. Install Remi repository for CentOS / Red Hat (RHEL):

rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-5.noarch.rpm ...and... rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm

4. Check Available Firefox versions:

yum --enablerepo=remi list firefox

5. Update or Install Mozilla Firefox 10:

yum --enablerepo=remi update firefox OR yum --enablerepo=remi install firefox

6. Fix the launcher at Gnome start panel by right clicking on the Firefox icon, then select 'properties'. Replace the string at 'command' field for the following:

/usr/bin/firefox %u

7. Done. Test it. Kudos!

6-5 is gone. Use this instead

rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-7.noarch.rpm

If 6-7 is gone, then use a browser to go to http://dl.fedoraproject.org/pub/epel/6/i386/ and find the correct file name.