K.D.
I wish you much luck in your search. Unfortunately I never found anyone suitable that we could afford. We took a hard look at our finances and decided that I was the best and most affordable care giver for our only child. So I became a stay-at-home mom. After our daughter started kindergarten, I launched my own business from home so that I could fulfill my career needs while still filling that all important mom role. I run Vantage Point Creations (www.vantagepointcreations.com) and would love to do a portrait of your son at some point in the future.
As far as agencies go... if you are willing to sign a one or two year contract, do lots of research with the BBB of the ones in your area before you sign. It usually takes 2-3 weeks to interview people and then about 2 weeks to train someone before you leave them alone with your child.
All my best wishes for you.
K.