After math.b3co.com went down, I needed a new source for my LaTeX conversion. There is an excellent converter available at ScienceSoft.at, but it's a hack to script it up. This page converts LaTeX fomulas to png — it automatically adds the necessary \begin{document} cruft — on a one-off basis; script access is available through POST.
Optionally, you may pass ?xml as a GET parameter, and the results will be returned as
<?xml version="1.0"?> <latexresult> <lateximage location="_url_" source="sciencesoft.at" /> </latexresult>
This way, you can avoid parsing all the surrounding cruft. Images are maintained locally, so you don't need to copy them to your home server (however, as a nice script kiddie, that's a kind thing to do); a PHP example of socketing/downloading will be up shortly. In the meantime, the general source is available here: latex.txt (please note that it's a script designed to work, not look particularly pretty).
Realistically, it's much better to just use the tool available at ScienceSoft.at — for one thing, there are many more options I've obfuscated, but even beyond that it's more polite to give them the pageviews — but if you have heavy formula-conversion needs (such as, for example, converting formulas to appear on a blog) then one-offing isn't going to cut it.