http://computerlabs.tcnj.edu/ provides a list of computer labs around campus. Every academic building (including the library) has one or more labs. Most of these labs offer PC machines, however a few are Mac based (the list specifies which ones).
Note that if you arrive at a lab, and the door is locked, your TCNJ ID card can be swiped to unlock the door. Also note that classes are sometimes scheduled during the lab hours listed on the page. Please check the lab reservations for the upcoming week on the lab door. These reservations will be posted every Sunday for the upcoming week.