In the US, a university offers at least 1 Master or higher degree in some field. A college's highest degree is an Associate (community college) or Bachelor.
A university will refer to it's smaller degree areas as College such as College of Educational, College of Business. This is to differentiate them from administrative departments. In the same vain, college's will have schools of education or business, ect.
In the UK (by what my Brit friends have taught me) college is more like US high school, and university is the education after that (the post secondary education). My friend's child would be in US high school, but is attending college in England.