Instant messaging didn't even exist when I was in school, but I've heard of professors using IM to let students contact them online instead of meeting them during designated office hours.
Here in the U.S. there are some universities such as the
University of Phoenix which offer online classes. Students collaborate on projects using a combination of email, discussion forums and instant messaging.
I've also heard anectdotal evidence of teachers using collaborate tools such as NetMeeting with it's whiteboard and application sharing to actually teach classes. Try this search on Google about
distance learning.
Of course, most students today are comfortable with IM, and use it regularly to keep in touch with friends and family.
Jeff Hester aka "Mister BigBlueBall.com"