From the KnowledgeBase
Wireless: How to configure your Mac OS X computer
Wireless networking is available throughout campus. The following information is for faculty, staff and students on campus. If you are visiting and need information on eduroam and PUvisitor services, see: www.princeton.edu/wireless.
In order to use OIT wireless service, your computer or wireless device must be registered in the University Host Database. If you're not associated with the University, use the Visitor Wireless service.
Connecting to the Network
This document assumes you are using Mac OS X 10.2 or later, with an AirPort card either built-in or properly installed in your computer.
Click the AirPort icon in the Menu bar, and make sure AirPort is turned
Select puwireless from the pull-down menu to connect to the network. If you are a visitor on campus, select puvisitor.
If the AirPort icon doesn't appear in the menu bar, select System Preferences from the Apple menu, and click on Network. Select Airport from the Show drop down box(Tiger or earlier) or from the list on the left side of the window(Leopard), and make sure Show AirPort status in menu bar is enabled.