Unfortunately, the process is not simple and not for the faint-at-heart! It
involves downloading the web  part XML and editing it so that it queries the
additional information you need. You also need to edit the XSLT that displays
the results to create a new display  style that shows  the additional  information.

The best reference I know is to use Heather Solomon's blog entry
www.heathersolomon.com/.../CustomItemStyle.aspx together with
the ECM blog entry that she links to in the first section.

Personally I find it much easier to build DataForm Web Parts in SharePoint
Designer, since it gives you a nice user interface to select the columns  you
want from the list and a WYSIWYG editor for presenting the results. However, you
need to hand edit the code to make them query  across multiple  lists the way a
content query web part  does. Let me know if you decide to go down that route and
I will dig up the information on how to do that.

It's exactly the kind
of step-by-step process I was looking for. I'll try playing with it myself and
see how far I can go.