Hi--
When you drop your kid off, you'll get a gate pass to take him/her to the gate, and you can stay there until the plane leaves. Note that you'll need to provide the name and contact info of the person doing the pickup.
On arrival, at most airports, the camp staff can get a gate pass to go to the gate. An inflight crewmember will bring the child off the plane and meet the camp person in the terminal.
Lots more info at
http://help.jetblue.com/SRVS/CGI-BIN...e,case=obj(675)
and
http://www.jetblue.com/help/topics/airports.asp