My latest WordPress article has appeared at the Peachpit Web Design Reference Guide — Customizing WordPress: Edit Theme Style Sheets:
If you want your blog to have a unique look, you must learn how to customize themes. A theme changes the look, layout, and even the content of your WordPress blog. There are many different ways to customize themes, but this article will get you started by explaining how you can edit the Kubrick theme’s CSS file to change the appearance of text in your blog.
Themes are a huge topic — we devote at least a whole chapter of WordPress 2 Visual Quickstart Guide to customizing themes, but if you’d like to take some easy steps, this article will get you underway.