Intellectual property

I was wondering if anyone actually knew if the university has any sort of rights to the things you create for assignments. Say I wrote a really good essay for a class (yea right!) and I had a chance to publish it, am I allowed? The more pressing issue is whether I can share the source of a program I wrote. Bearing in mind that this was actually an assignment where I had to choose what to do. So it would be my belief that I should be able to continue working on said ‘assignment’ and make it open source - after they have been marked and returned of course. Hmmm… I’m going to assume that I can unless I find otherwise :)