David Johnson at infoplease has given out some information on psychology and color. He has a good list of colors which associate with different meanings and some of the affects from the color. For instance, yellow is a very good example:

Cheerful sunny yellow is an attention getter. While it is considered an optimistic color, people lose their tempers more often in yellow rooms, and babies will cry more. It is the most difficult color for the eye to take in, so it can be overpowering if overused. Yellow enhances concentration, hence its use for legal pads. It also speeds metabolism.

Remember different cultures has different meanings. The article’s meanings are for western culture.

Psychology of Color – [infoplease]