Interesting Harvard study showing some increasing trends toward moderates, especially in community colleges, but still almost no conservatives at elite liberal arts and research institutions, particularly in the humanities and social sciences.
http://chronicle.com/daily/2007/10/2007100801n.htm
Here's a report on a follow-up conference from the American Enterprise Institute.
http://www.insidehighered.com/news/2007/11/14/aei