If you check the link I gave above, you'll see that it's actually very easy. You don't need much CSS knowledge at all to put the child theme together and get it working. Once the child's stylesheet has been set up, you can use the CSS @import to pull the parent's CSS into the child. so, for a child of Twenty Ten, you'd have something like:
Theme Name:My Theme
Theme URI: [Put your site's url here]
Description: A custom child theme of Twenty Ten
From then on, you only need to add the CSS (or template files) that you want to change.