One of the things I've written recently for WordPress/ComicPress is a little plugin/widget called, aptly, Featured Comics.

Featured Comics Plugin/Widget

Featured Comic is a small sidebar widget that lets you scan a link category, then "feature" a random link inside of the specified category on the front page. Supports images, update times and rss-feeds for current links.

To use, set up your Link Category that you want scanned, create the link to the comics, including images, rss-feed, artist's name in the Description field, and update times in the Notes field. Activate the Plugin, go to your widget controls and move the widget to where you would like it in your layout. Set the category you want scanned, select your options on what you want shown, and optional background image url and optional background color #code, hit save and your done.