I've added math typesetting support to Ocsiblog, which runs this site, using jsMath: (double-click on the equations to see the sources)
\[\begin{eqnarray*}
\nabla.D & = & \rho\\
\nabla.B & = & 0\\
\nabla\times E & = & -\frac{\partial B}{\partial t}\\
\nabla\times H & = & j+\frac{\partial D}{\partial t}\end{eqnarray*}
\]When jsMath is enabled, you'll see in the bottom right-hand corner a button that triggers a control panel allowing you to set several options such as the scale or the rendering mechanism (TeX fonts, image fonts or native Unicode fonts; you can pick the one that works best for you and save the configuration --- the best one is TeX fonts, if you have them, but Unicode fonts is quite decent). For best viewing, you can get the TeX fonts here (the page includes detailed install instructions for Windows, OSX and Un*x).
Here's what the above equations should look like with TeX and native Unicode fonts: 
