search for a group on meetup.com. also try dc urban moms (google it) and www.our-kids.com. i also find activities in Washington Family Magazine and the local paper. getting your kid involved in things will get you involved in the parents. many times just heading out to the playground, swimming pool or library will get you and your son in touch with other people.
sometimes the mom's you meet out with your kids become good friends. then you have someone to swap babysitting with or to hang out with while someone else watches the kids!
and don't be embarrassed!