For installation just copy the exceltex helper script somewhere in your
PATH for example $HOME/bin or /usr/local/bin, and make sure it is
executable.

The readimg.sty file should be copied somewhere LaTeX can find it, usually
$HOME/texmf/tex/latex/misc or /usr/local/lib/texmf/tex/latex/misc. Dont 
forget to run 'texconfig rehash' afterwards.

Thats it.

