So, I stumbled across some totally excellent Cheat Sheets today available for free!
They cover a bunch of web programming topics including: Javascript, CSS, HTML, MySQL, PHP, and Ruby on Rails.

http://www.ilovejackdaniels.com/cheat-sheets/

They include great function references and things like that. The best thing about them is that they are absolutely beautifully designed. Many thanks to the author for making these available.