Here’s the installation instructions using remi repository for Mozilla firefox 4 final release on Fedora 14 Laughlin. Also check Mozilla Firefox 4 quick look at new features and installations instructions for different distributions Here.

Install Remi package for your distribution whatever it’s Fedora 14 Laughlin from Here.

Firefox 4 Installations for Fedora 14 Laughlin

Run terminal, then type

Firefox 4 installations for Centos and RHEL

Firefox 4.0b8 worked on CentOS 5.5, but 4.0b9 has a problem with the revision of the C++ library and won’t run out of the box. All is not lost though, because you can use Fedora 9′s C++ library instead as follows (some of this may need sudo/root access):

1. Unpack the Firefox 4.0b9.tar.bz2 somewhere (e.g. /usr/local/firefox). With the “en_GB” release, I throw in a “dictionaries” sub-dir under there with en-GB.aff and en-GB.dic in there (and en-US.aff/.dic soft-linked to the en-GB ones) otherwise, sadly, Firefox 4 uses US spellings on what’s supposed to be an en_GB release 

2. Download this 32-bit Fedora 9 libstdc++ RPM and unpack it with this command:

rpm2cpio libstdc++-4.3.0-8.i386.rpm | cpio -i –make-directories

3. Move the unpacked shared library into /usr/local/firefox thus:

mv usr/lib/libstdc++.so.6.0.10 /usr/local/firefox/libstdc++.so.6

Note: It’s “usr/lib/libstdc++.so.6.0.10″ above (i.e. the unpacked tree from the RPM, not the system /usr/lib tree) – do NOT put a leading slash there!

4. Run Firefox 4.0b9 with:

/usr/local/firefox/firefox

Or you can install last stable release of firefox from Here and compile with installations instructions on readme file.

This’s the English version of Firefox 4.0 for other languages install suitable extensions 32bit, 64bit.

Centos and RHEL installations instructions Source