Include LaTeX formulas in HTML files?

MathJax is a possible solution. It is a client-side solution (Javascript) which is compatible with LaTeX syntax.

I think MathTran provides an online outsourcing of your LaTeX files, which you can later embed in your HTML code (much in the way of the Google Chart Tools)

Depending on your server configuration (ie assuming you can install what you want), if the LaTeX files don't change often you could easily schedule a (say) LaTeX -> PNG render (lots of info the web on how to do it) and link the resulting PNG.

Last resort (but the simplest) if you have server limitations (say a shared host), you can just render the LaTeX to an image offline and upload the result.