There is an outstanding defect on the site where old links no longer work. You can see this if you google search for mathhelpforum posts and find old links that are broken. More details here.

The page formerly gotten to via

http://www.mathhelpforum.com/math-help/latex-help/

is now found at

http://www.mathhelpforum.com/math-help/f47/

Not sure about the software bit but you might find this site useful

Online LaTeX Equation Editor