If ePrint is not already installed on your Mac, you first need to run the ePrint Popup Client Installer.

Double-click on the Popup.dmg file to mount the disk image, then run the Popup.pkg Pharos Popup Client installer.
Click Continue at the Welcome and Important Information windows, then select the hard drive where you wish to install the ePrint Popup Client.  Click Install to begin; you will need a username/password with administrator rights on the system to continue.
The software installation will continue. 
Press ‘Close’ when the installation is complete. 
The Popup Setup Assistant will automatically launch; select this application in the OS X dock.
Enter the following settings in the Server Address field:

Server Address: oitepps01.oit.duke.edu
Server Port: 28203
Server Timeout(s): 30

Then press Continue.  On the next screen, accept 28212 as the default client port, then press Continue again.
On the Enable Popup window, the application should tell you that Popup is currently enabled on this machine.
If not, click the Enable button.
Press Continue, then press Done at the Conclusion window to complete the setup.

Once the Pharos Popup Client is installed, you need to install your chosen ePrint printer locally on your computer.

Open Printer Setup Utility in /Applications/Utilities/.
On Mac OS X 10.4, click the Add button in the toolbar, then hold down the Option key on the keyboard and click the More Printers... button. On Mac OS X 10.3, hold down the Option key on the keyboard and click the Add button in the toolbar.
From the topmost popup button, select Advanced.
From the Device popup button, select Pharos Print Server.
In the Device Name field, enter a name for the new printer queue.
In the Device URI field, enter the Unified Resource Identifier for the desired Popup queue on a Pharos Print Server.
For Nicholas School printers, enter: popup://oitepps01.oit.duke.edu/queuename  (where queuename is ePrint-NSEES-BW)
From the Printer Model popup button, select the type of printer associated with the Popup queue.
If an exact driver for the locally installed printer/MFP is not available, selecting Generic or an HP 4/4000-compatible driver will work in most cases. You may also wish to check the vendor’s web site for an updated driver.
Click Add. The new Popup queue will now show up in the list of printers.
To print to the new queue, select it from the printer popup button in the print dialog of any application.