Hi J.,
I belong to a GREAT mother's group http://sahm.meetup.com/1657/?gj=sj3 . Most of the moms are SAHMs, although a few work, like me. They are a very friendly, outgoing crowd, who have playdates, parties, mother's nites out, tours of kid places, etc. When I first joined one of the meetup groups, I was a little shy, but I forced myself to post a few responses on the message board, and then forced myself to go to a playdate. It was the best thing I could have done. My kids made some great friends, but even more exciting, is the fact that I made some great friends too. My son just turned 5 in December, and my daughter will be 4 in March. A majority of the kids in the group are under 5, but not all. There are a few older boys that your son could get to know too. Check out our website, you won't regret it if you really want to make some friends. Oh, I almost forgot, most of the moms live in the southwest part of the valley... close to the Mts Edge area. =)