Computer science = Focused on the design and development of computers (usually software focused).
Information systems = Focused on managing computer systems and making sure they are working properly. Also focused on designing and implementing computer solutions.
Information technology, never heard of. I think it is one of those majors at a vocational school where they focus on stuff like pc repair and crap like that.
I would recommend computer science since almost all employers will take it as an equivalent to any of the other computer related majors.
