I'm surprised to see there isn't a NYC thread already going on this forum. I figured from sheer virtue of the huge population there'd be a considerable presence of gymnasts churning their way through Foundation. Maybe there is, and you guys just haven't gotten a thread going so here's one now.
I'll be moving there in a few days and will be around for a few months. I train Foundation (F1 and 2), Capoeira and tumbling. Last time I was there Chelsea Piers was my home but I'm going to look for other places as well (that are hopefully a little more affordable).
Edit: Hijacking my top post to let everyone that Transform Fitness NYC on 58th and Lexington is the definitive place in Manhattan for GST. I'll make a post about it as well, but I recommend looking them up on Mindbody to get the current schedule.