(I assume you're talking about the sort of job you see in Bones and CSI.) Forensics is a broad term for any sort of applied science that is used to uncover evidence.
What do they do?
- Forensic psychologists are common. A forensic psychologist might work as a "profiler," one who examines evidence and comes up with a personality profile of a criminal. More often, however, forensic psychologists are employed by the courts to administer psych evaluations for legal purposes. When someone enters a plea of "insane", it was a forensic psychologist who made the determination that the defendant is actually insane.
- Forensic anthropologists are becoming more common. They are scientists who examine the remains of humans so as to ascertain the cause of death and to get clues about that person's life. Medical examiners do much the same thing, but a forensic anthropologist will often be more experienced with skeletal remains or long-dead specimens. For instance, I know a forensic anthropologist who studies slave graveyards to learn about the diets of American slaves. I know another who specializes in burns - with knowledge of burning like he has, he can made very specific determinations about the origin and effects of a fire, and whether or not a person died before or after being burned.
What do you need to study?
- To become a forensic psychologist is tough. There are very few forensic psychology programs around, and they are usually closely associated with criminal justice programs. So: if you don't like cops, then don't get into this field of study. I doubt there are any undergraduate programs in forensic psychology, so you should probably start out in a BS program for clinical psych, sociology, or criminology. After that, you can head to graduate school and enroll in a program that specializes in forensic psychology. Sam Houston University is the only school off the top of my head that has a specialty in forensic psychology, but there are maybe a dozen others in the United States.
- To get into forensic anthropology, start off with an undergraduate degree in physical anthropology, biology, or archaeology. Get a good grounding in anatomy and the human body. There are several programs around the country that offer graduate degrees in forensic anthropology, but the only one I know of off the top of my head is University of California at Santa Cruz.