They do taste great. Here is a video on how to fillet them. As far as cooking them, use a beer batter recipe or just season them, put some corn meal on them and introduce them to some hot grease.
FILLET CRAPPIES AND OTHER FISH
http://www.youtube.com/watch?v=bqCoph-C6Jo
http://www.youtube.com/watch?v=JQXIbS5Y-Qs