I recently got very interested in these too. Personally I find these companies easier to understand. The have unique risks/qualities associated with them, are under followed, less liquid, management/majority ownership is usually a bigger deal, but there are definitely some interesting companies in there.
Some good resources to find some quality names are
http://www.oddballstocks.com/
http://otcadventures.com/
http://www.whopperinvestments.com/
http://ragnarisapirate.blogspot.com/
Personally I own or I am waiting to own some of the names below
AMNF,TLF,ARTW, MPAD