I believe all Macbook Pros are capable of rotating their internal display. Tiger may allow you to do that using System Preferences: Option-click on the Displays pane in System Preferences and a display rotation drop down box may appear.
If that does not work, the Unix utility fb-rotate will. It is available here:
http://modbookish.lefora.com/2010/06/29/a-unix-utility-to-change-the-primary-dis play-on-os/
You probably have to re-compile the source (fb-rotate.c) for Tiger, but there are instructions on how to do that, and it is easy.