A friend of mine mentioned they use WinEdit to originate LaTex math documents. I checked and it appears it does not give a WSIWYG preview or working environment. I will have to install to verify.
WinEdt is a shareware Unicode (UTF-8) editor and shell for Microsoft Windows. It is primarily used for the creation of TeX (or LaTeX) documents, but can also be used to edit HTML or any other type of text file. It can be configured to run as a front-end for a variety of TeX systems, including MiKTeX, fpTeX and TeX Live. WinEdt's highlighting schemes can be customized for different modes and its spell checking functionality supports multi-lingual setups, with dictionaries (word-lists) for many languages available for downloading from WinEdt's Community Site. It supports DVI and PDF workflow.