I would like to introduce mimeTeX to people who is interested at webdevlogs and wikipedia's math equation images.
The images, like this one

are generated by LatexRender, a system uses LaTeX, ImageMagick, Ghostscript. It's likely your server does not come with any of the libraries mentioned above, so, mimeTeX become the next alternative.
Here is what a mimeTeX rendered math equation that can find out my birthday.

It is slightly less attractive because it have zigzag edges, but other than that, mimeTeX works.
If you have no control over the installation of new CGI scripts, there is a mimeTeX API.
For example:

<img src="http://www.forkosh.dreamhost.com/mimetex.cgi?c=sqrt{a^2+b^2}"
   alt="mimeTeX showoff" />

results this:

Are you a PunBB, Movable Type, Mambo, WordPress or phpBB user? Good for you, there are mimeTeX plugins for those system, go and do some search.