Tips for someone who wants to learn CSS?

So, I've been keeping a pretty regular blog on Wordpress for about six months now, and I think I'm ready to take the leap into getting my own domain, and to use a new layout unique to my blog.

The problem is, I don't actually know CSS. I looked around the internet, but couldn't really find anywhere to start to learn that made any sense to me. I know a fair amount of HTML, but the whole 'meta' business is still a bit foreign.

So, anyone have any advice on how/where to start, or what specific things I need to know before I jump into learning CSS?

(Note, if anyone wants to check out the blog, or actually help me make a CSS stylesheet -- nothign fancy, don't worry -- you can see the link below for the specifics.)