I've been doing a lot of math this semester, and I am coming to realize more and more that I need latex. I've grown used to using ms word's equation editing feature to the point that I know most of the escape sequences, but I need to move to latex for several reasons. To name a few: Not everyone can read my documents; Word is not "formatting friendly (for example I can't number equations); and most importantly I need macros to speed up my homeworks and such.
Given my needs, what software (preferably free) do you recommend I download, in which I can use macros, create files I could send via email, and easily preview my equations (automatic preview-as-you-type would be nice)?
Also, what's a good resource to teach Latex (for a beginner, say)?