This interesting wasp is an Ensign Wasp one of the members of the Evaniidae family. Quoting my efriend Roy " They are parasitoids of cockroach oothecae [egg cases] . Not really uncommon but, are still really neat wasps nonetheless." This individual was photographed in Port O'Connor on August 23, 2010 as it was on a door. This individual was ~1.5 cm long.
Thanks Roy, Linda and others for your comments.