Hee check this website out for latex equations
Sitmo is also another good one (www.sitmo.com). I added that to my iGoogle front page when I start up my browser. It's pretty darned handy.
What's an iGoogle home page?
Cool! I just added it to mine.
It's a personalized Google page to which you can add all sorts of cool gadgets. Excellent!
Somewhat similar, here is a LaTeX-based IM (chat) webpage. Rather helpful if you are trying to explain something which requires loads of math.
Sitmo is better then mine because it updates in real time, Thanks.
Also try http://www.formulasheet.com/editor.php, it also updates in real time.
Separate names with a comma.