Movable Style
The site Movable Style is dedicated to showing off different style templates for Movable Type. Change the "Styles" drop down menu to instantly change the look of the site.
You can download the style sheets and put them in your own blog. If you want to change your blog to one of these looks, let me know.
When you log into MovableType there is a help button at the top that explains how many things work.
Kelly went in and changed a lot of the colors in her style sheet. I helped her clean up her changes, so her blog is unique looking. I think she did a good job.
This article explains how your Main Index template is made and how your style sheet controls the look.