I think it is great that you want to do this. I took my Golden through a couple of classes in Marin and Sonoma County and unfortunately they did cost.
I agree that looking up information on the net is a great idea. The Delta Society has books you can buy but you should find a place that will cover your liability in case something happens. When I visit as a representitive of the Marin Humane Society I am covered under their insurance.
We visit two facilities right now, one a long term transistional housing center for people with Mental Illnesses and the other is a boys home for kids with emotional and physical problems.
Good luck and let us know how you do.