One of my favorite little programs is LaTeXit.  It allows you to typeset LaTeX equations outside of a text editor and then drag the results into programs like Keynote or Pages.  It was not fully compatible with Leopard and my fix was a kludge that could break other programs.  Pierre Chatelier has released updated LaTeXit to version 1.15.0, which restores Leopard compatibility.  Notably, you can now use the default0 /etc/profile file without fear.