LaTeX.org

Hello.
I am trying to make a little forum for me and my friends. What I want to do, is to make latex codes like this:
[tex]\frac{5}{7} \cdot \sqrt{5} + \pi[/tex]
Look like this:
http://texify.com/img/%5CLARGE%5C%21%5Cfrac%7B5%7D%7B7%7D%20%5Ccdot%20%5Csqrt%7B5%7D%20%2B%20%5Cpi.gif

I am using ...