Composing Mathematics Papers

I was just wondering if anyone had recommendations for programs/document editors that are good for putting together professional-looking formulas and papers? Free and Windows-compatible is always nice, but "free" non-windows apps would work as well. A quick googling led to nothing of use.

Thanks guys.

>>7
put \usepackage{package_name_without_cls} at the top of your tex file, just below \documentclass

where the cls file needs to be depends on your tex installation, sometimes just having it in the same directory as the tex file you're editing is enough.