The errors I encountered and the libraries I had to install to get Mozilla Firefox 3.6.28 running on Fedora 18.

./firefox
./firefox-bin: error while loading shared libraries: libgtk-x11-2.0.so.0: cannot open shared object file: No such file or directory

yum install gtk2.i686

./firefox-bin: error while loading shared libraries: libXt.so.6: cannot open shared object file: No such file or directory

yum install libXt.i686