Pete Freitag has collected a whole list of "cheat sheets" in this new entry on his weblog today.

Lets face it, unless you have a photographic memory, no developer can remember all the different functions, options, tags, etc. that exist. Documentation can be cumbersome at times, thats why I like cheat sheets. They are quick references that feature the most commonly forgotten things on a specific topic. You can print them out and hang them on your wall, or just keep them handy in your bookmarks for quick reference.

I have rounded up over 30 cheatsheets that developers might find useful.

He has all sorts of sheets included - some for languages (PHP, Ruby, JSP, etc) and others for general web development (Javascript, CSSS, HTML, etc).