Enter latex directly in your blog

There are many ways of showing Latex formulas in blog. Of those, maybe the simpliest one is to use the CodeCogs site like this:
<img src="http://www.codecogs.com/eq.latex?\tiny \int_{-\infty }^{\infty }x^2 e^{-x^{2}}\;dx = ?}" /&gt; would appear as
and another similar way:
<img src="http://www.forkosh.dreamhost.com/mathtex.cgi?c=\sqrt{a^2+b^2}" title="c=\sqrt{a^2+b^2}" alt="c=\sqrt{a^2+b^2}" style="vertical-align:-2pt;" /&gt; looks like


replacing "http://www.forkosh.dreamhost.com/mathtex.cgi" with "http://www.sitmo.com/gg/latex/latex2png.2.php" also works.