Both MAFFI and MARC are national organizations with lot of information available.
MARC - Model A Restorer's Club
MAFFI - Model A Ford Foundation, Incorporated
And when you want to make your car go fast, check out the Secrets of Speed Society.
Secrets of Speed Society
On a more regional basis, Northern California Regional Group hosts several events during the year.
Northern California Regional Group (NCRG)
These links might also be of interest to you, providing useful information and some interesting pictures.
AHOOGA "Around the World"
Friends of the Model A Ford
John's Old Car and Truck Pictures and Many Other Things