This is the link to most of the main assignors in the area.
http://www.iacao.org/area_assignments.htm
This is the link to all the associations in the area.
http://www.iacao.org/iacao%20members.htm
If I were you, I would contact the associations first and go from there.
You do not have to join an association to work games in baseball, but it is a great place to make contacts and to learn more about the system in our area.
Peace