Lyx

In more Detail...

Document production system that acts as a front-end to latex. So
it (potentially) has all of latex's features but you can use it
without knowing any latex, plus you can see equations, tables, 
etc. on the same screen you're typing. Open source. There 
is no Mac version (yet). Read below for the windows version...

Platform: Linux
Exec command: [/home/p/demo/demo/bin/]lyx
Documentation: help

Lyx for Win: The windows version works ok,
but installation is not automated. Get all from 
http://www.demo.cs.brandeis.edu/~pablo/lyx/... 
or go to www.lyx.org for more info.