X11 on MacBook Pros
As of August 2007, Apple made a real effort to hide X11 on Tiger install disks for MacBook Pros. It doesn’t get installed by default, and it’s not available through the installer. To get it, insert disk 1, open Terminal and run:
open /Volumes/Mac\ OS\ X\ Install\ Disc\ 1/System/Installation/Packages/X11User.pkg
Update: OS X 10.5 Leopard installs X11 by default and features tighter integration between the two, so the above procedure is no longer necessary.