At any decent university, both a CS and IS degree will teach you to build applications.
IS adds in the business side, and less of the theory side, compared to CS. Generally, there is more demand for IS than CS. Software companies hire CS people because you need people who really understand theory. In reality, most IT in the corporate world is using existing tools and integrating them, so that's IS. You'd be hard-pressed to find a corporate IT person who has written a sort routine in ages -- existing tools already do this. A CS person may need to do this if they're writing some framework or high-scale system and need to optimize, but that's just not most of the IT world.
IS adds in the business side, and less of the theory side, compared to CS. Generally, there is more demand for IS than CS. Software companies hire CS people because you need people who really understand theory. In reality, most IT in the corporate world is using existing tools and integrating them, so that's IS. You'd be hard-pressed to find a corporate IT person who has written a sort routine in ages -- existing tools already do this. A CS person may need to do this if they're writing some framework or high-scale system and need to optimize, but that's just not most of the IT world.