What do you need to do if you want to give IQ tests? What sort of college major?

Answer 1

You'll major in psychology and will need at least a masters degree. School psychologists can administer IQ tests. Neuropsychologists(PhD) and speech pathologists (MA/MS)do the same.

Answer 2

You'll need a graduate degree in Psychology (not necessarily clinical psych, although clinical psychologists do all sorts of testing). A better question might be what are your goals besides just giving IQ tests, and then we can probably provide more thorough answers. :-)