I don't know of any formal rec climbing clubs in NJ but Climber020 on this board and Electrojake and JerseyEd on the TCI board do some rec climbing in Jersey. You might try posting in the TCI (Tree Climbers International) message board and see who you can flush out: TCI forums
Yeah Dean if you ever want to get together sometime I work in your neighborhood all the time. I try to go some rec. climbs when I have the time. Just let me know if you want to get together and I could help you out a little.
Climb020 - you know, that would be great. I have no problem getting down to Bordentown, its only 35 mins away. I'd love to take a look at some equipment and maybe watch you do a climb if that's convenient.