Over at Mother Jones, Nick Baumann has a superb interview with one of Loughner's friends, which sheds considerable light on the workings--if you can call them that--of Loughner's mind.
http://motherjones.com/politics/2011/01/jared-lee-loughner-friend-voicemail-phone-message
http://motherjones.com/politics/2011/01/jared-lee-loughner-friend-voicemail-phone-message