StyleCatcher is a simple but powerful plugin that lets you easily swap out any one of dozens of different styles on your Movable Type-powered site. The plugin also allows you to use other style repositories, so you can get styles that aren't provided by Six Apart.

To utilize StyleCatcher, you must first define the Theme Root URL, Theme Root Path, and an optional Style Library URL, so that themes can be stored locally on your server. You can do this from the System-wide Settings Plugins' screen.

Once that has been configured, running StyleCatcher allows you to find styles and themes from style libraries, and apply those styles to your weblogs.