Also, Simon found this and posted it to GameSetWatch
How to Be a Game Designer
There is no precise set of requirements for becoming a game designer. Most designers come from different fields of computer arts, programming or directly out of QA and I could totally see people from science or psychology fields orienting themselves in the video game field. In fact, the more diverse are your knowledges, the better.
(My emphasis). I hear that point from game designers again and again. Good ideas come from cross-pollinating intellectual interests. The best designers I know - and just reading their blogs will reveal this - are actively curious, well-read, pursue hobbies, and participate in a number of different disciplines.
I don't know that you can find a program in a school that will teach you this, unless it's a liberal arts education...