[cma]

This helps so much:

http://en.wikipedia.org/wiki/List_of_mathematical_symbols

[CatMtKing]

Hmm, remind me to write a handwriting-recognition program to search through that.

[jpfr]

Someone already did exactly that. http://detexify.kirelabs.org/classify.html

[rahimnathwani]

This is truly awesome. It's just like using a Chinese dictionary with handwriting input (like Pleco or Nciku).

I don't use LaTeX but now I'm looking for an excuse :)