Since moslatex does not upgrade for Joomla 1.5x, MathPublisher plug-in can be used for displaying mathematical equations. The plug-in uses phpMathPublisher, and so will not handle a complicated math typing. But it is good for most symbols. Here is an example of a mathematical equation: $a^2+b^2=2011$. (Note. This site now uses MathJax to handle $\LaTeX$ equations. See the post: LaTeX enabled using MathJax.)