It will vary widely from school to school. When I got my CS degree, I was actually a double major in CS and Math. At the time, you only needed to take 1 additional Math class over those required for CS in order to get a Math minor.
The basics were 2 years of calc (the second year including Diff Eq's) plus a class in linear algebra. There was also a requirement for a class in sadistics.
For my double Math major I had to take a different linear algebra class (one designed for math majors instead of CS majors) then I had 5 semesters of senior level math classes which I loaded up with number theory and numerical analysis.
As for what you need before college, again at the time I took calc in high school, took the AP exam and passed out of the first year of calc in college. Those that didn't have the calc in high school were merely stuck with taking the first year calc in college. If you take calc in high school and don't bother with the AP exam, then it will simply make the first year of calc in college easier as it will be a lot of review. Some colleges will also allow you to test out of calc, and still other colleges will have a program with local high schools whereby if students take a special calc class in high school they get credit at the college if they attend there.