J.C.
Is Norristown in Montgomery County (sorry...I can't recall...)? If so, you may want to check out www.BuxMontmommies.com. They just started the chapter in this area recently, but they seem very organized and efficient, although to accomadate both Bucks and Montgomery Counties, the playdates are occasionally a bit of a drive. Norristown is probably about 45 mins or so from where I live...My son just turned two in September. I work full-time Monday through Friday, but would be available for weekend playdates, if you'd be interested :)
And, www.matchingmoms.org is a great site geared toward helping moms with little ones meet up for playdates and such within their local area. I've met a few pretty good friends for both myself and my son through that site who we see on a pretty regular basis. It's free to register, so it can't hurt to give it a try :-) I've also found moms.meetup.com/ but didn't find exactly what I was looking for...maybe you'll have better luck in your area.
HTH-
J.