RPM of the first RC of next major version of Mozilla Foundation browser is available in remi repository for Fedora >= 10. Available for 80 locales.
The firefox4-4.0-0.28.rc1 package install this new version besides the version 3.x. So you will have 2 entries in the Internet menu. Start by reading : Mozilla Firefox 4 RC Release Notes As always : yum --enablerepo=remi install firefox4 If you prefer to replace the system firefox, you can also install firefox-4.0-0.28.rc1 from remi-test... Lire Firefox 4.0 Release Candidate 1