Really, really easy. I figured out that I have a two column blog. Went to Shabby Blogs and picked a new background. Followed the simple installation instructions and just like that... A whole new look.
I thought I wanted something blue, but I have to say, I like this. And, if I get a deep, dark hankering for blue in the future, I can always change it, now that I know how.
Now to work on a new header to go with my snazzy new background. :D