I would definitely encourage it.  My Aunty was on my case for ages to make a proper one and I didnt until I was onto my second industry role.  Looking back, I wish I did because I could have really developed my profile much earlier.  LinkedIn is a great and simple way to network and grow your brand, so definitely get a start early on.  When I get more time, I plan on developing a guide to LinkedIn for uni students because I do think it is an excellent resource.
I also agree with Seremify in that if you do make one, do it properly.  A half-hearted one isnt really worth wasting your time on in my view.