i'm going to one now in woodbridge, not sure if that's too far for you, the class is 6 weeks and it's closed for this cycle, they might have another one after that. we are on our second week now.
I am currently taking prenatal yoga at Soul Power Yoga in Marlboro (at the corner of Rte 520 and Rte 79). It has been great. The instructor is very knowledgeable and you can drop in for single sessions or buy 5 or 10 at a time. I've been very happy with it!
Re: Prenatal yoga