MathJax
Beautiful and accessible math in all browsers
...MathJax is highly flexible and can be tailored to the needs of your institution by creating customized configurations and specialized software workflows. MathJax uses CSS with web fonts or SVG, instead of bitmap images or Flash, so equations scale with surrounding text at all zoom levels. MathJax is highly modular on input and output. Use MathML, TeX, and ASCIImath as input and produce HTML+CSS, SVG, or MathML as output. MathJax works with screenreaders & provides expression zoom and interactive exploration. You also can copy equations into Office, LaTeX, wikis, and other software.