First, make sure you have python installed.
$ python -V Python 2.4.3
If you do not have Python 2.0 or better, you'll need to download and install Python. (CrossTeX has been tested with Python 2.3 and 2.4.)
CrossTeX also depends on Ply, the lex and yacc tools for Python.
Download and install platform-independent RPMs for Ply and CrossTeX from SourceForge. If your system already has a ply package and it is installed, there is no need to use the one from SourceForge; it simply installs Ply into a CrossTeX-specific directory for portability and meets the dependencies of the crosstex RPM package. A system-wide installation of Ply is likely to be of more use, if available.
First download and install Ply.
$ wget http://www.dabeaz.com/ply/ply-2.2.tar.gz $ tar xzf ply-2.2.tar.gz $ cd ply-2.2 $ su - # python ./setup.py install
Then, download the latest CrossTeX distribution, untar the file, and install it as root. Then see if it worked.
$ tar xzf crosstex-*.tar.gz $ cd crosstex-* $ su - # make install # exit $ crosstex --help
If all went well, a list of command line options should be displayed.
To install into a directory other than the default (for instance, if you do not have root access), download the source versions of the packages, extract the code, go to the ply directory and invoke setup.py script with the option --prefix dir, then go to the crosstex direcory and install CrossTeX with make PREFIX=dir install.
If you are using RPM and have root access, you can install CrossTeX with rpm -i --prefix dir crosstex-*.noarch.rpm.