University of Toronto researchers have created a fantastic animated introduction to the cellular and molecular biology of the neuron. The introduction is divided into eight thematic chapters (e.g. "Anatomy of a Neuron", "Action Potential"), that explains the basics of neuroscience using interactive text and accompanied animations. Highly recommended.
By the way, the Society for Neuroscience's "Brain Facts" booklet (downloadable for free as a pdf) is also a useful introductory resource.
(Via Science's Random Samples).