I find myself working with the Sphinx Documentation Generator a lot recently. It is a great tool to easily create intelligent and beautiful documentation and it is based on reStructuredText. I put together a cheat sheet of all the commands I frequently use. There are a number of very good ones out there ([1] [2] [3] [4]) but I find it more convenient to work with my own.
You can access the PDF from here and the source (OpenOffice Writer document) here. If you find it useful or would like an item added, feel free to leave a comment.