Here is a collection of cheat-sheets which I use. Believe me they are very handy and can save a lot of time while development.
Mootools 1.2 cheat sheet
Django 1.0 cheat sheet
CSS Shorthand cheat sheet
XHTML Character entities
HTML XHTML Quick Ref
HTML XHTML Characters
Browser W3C DOM Compatibility Modes
CheatSheet Collection : Cheat Sheet for web developers
On April - 11 - 2009
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