What is the difference between sociology and psychology?

The difference between sociology and psychology, generally
speaking, is the difference between the group and the individual.  Sociology focuses on the ways
in which groups affect people and their behavior while psychology focuses on the individual-level
influences on behavior.

For example, if you wanted to explain why I
have a certain set of beliefs, you could go at it a couple of different ways.  A sociologist
might look at what sex I am, what race, and what income level.  They would try to explain my
behavior based on those factors.  A psychologist might look at my place in my family's birth
order, my relationship with my parents, and other personal attributes like
that.