As far as whether IS/IT degrees fall under science, mathematics, business, or their own college really varies by institution. A number of large university have created colleges of "Information Science & Technology" in which case IT degrees fall under IT. The whole concept of an IT degree falling under math/science or business is becoming outdated.
Degrees are paper. I've hired people with masters degrees in CompSci, their MCSD, and they also taught undergrad programming classes as adjunct professors and when they get to work they can't code worth a damn. Likewise, I've hired 19 year olds who have nothing more than their high school diploma but turn out to be excellent developers. A college degree has more to do with follow-through and achievement than a realistic litmus test of what people may or may not know.
Many schools are offering concentrations now. For example, you could get a degree in Computer Information Systems with a concentration in Software Programming, Networking, Database Management, Network Security, etc. It varies by school. Private schools always seem to be more current than state schools when it comes to degrees that apply to current employment trends.