University of Texas at Austin
University of Texas: Neurons and Neurotransmitters
A good description of how the neurotransmitters are involved in cell communication. Very good site.
University of Texas at Austin
University of Texas: Other Neurotransmitters Compared to Dopamine
Site provides the main function of the neurotransmitters serotonin, norepinephrine, acetylcholine, and glutamate.