What does it take to get into a graduate math program and how are they?

It varies from school to school (or Department). But it also requires a minimum of about B- overall GPA and B+ plus so in the field of study. Some schools (or departments) also require the GRE (grad rec exam) which is monstrous exam sometimes taking one and one half days. Then you usually have to get some faculty support. Other universities have varying requirements. Read the catalog.