If you haven’t come across the cheat sheets site for MySQL, PHP, mod_rewrite and CSS then go take a few minutes and check it out. Most of these are things that I usually only often enough that I remember where to look information but not the actual information itself, so these cheat sheets should come in handy. I recommend using the PDF versions for printing over the PNG versions, I was able to get much better print quality out of the PDFs.
I’d love to see a few more these for MS SQL server, Oracle, PostgreSQL and Vim.