Webmonkey, which I found while doing in ICM 501, is a great resource. I like the fact that it is at the "Primate" level of skill and yet has a 4-out of-5 banana rating. For those who aren't into coding and have a hard time remembering what kind of tags go before what you want to do, it's great to have open in a different window to reference.
This may be my new favorite coding assistant. I found it on the Web Developer's Handbook, as linked to from CSS Zen Garden's CSS Resource Guide. Seriously, this rocks.
Here's an interesting site I encountered looking for CSS cheat sheets. I'm not sure how useful it might be, it because the entry is dated 2006. But the eye-candy on the page attracted me.