You will only need to install AppleTalk if you are printing from OS X.3 to Windows 2003 Server. All other supported OS combinations will connect via Windows Printing.
See Also
Preparing the Software to Receive Jobs from Clients
Installing the AppleTalk Protocol on Windows Server 2003
Setting Up File and Printer Sharing
Windows Client Setup
Macintosh OS X Client Setup
Sharing PPDs over a Network
