Many! More fields are developing each year. The most common are:
Experimental-Testing and drawing conclusions from research
Clinical/Counseling- Working with people who have severe psychological disorders or everyday people who may need therapy
Developmental-Study the mind at each of the different stages in a humans life
Industrial Organizational-Often work in Human Resources and are consulted in the work setting to help with productivity
Social-Study how people interact with each other in different cultures or social circles
Physiological/Neurological-Study the brain and the biological reasons we act as we do