http://www.apa.org/science/programs/testing/index.aspx
The A.P.A.'s "Testing and Assessment" page has a link to a FAQ about psychological tests and how to find information about psychological instruments.
http://www.testpublishers.org/
A list of test publishers, their products and services.
http://www.unl.edu/buros
Includes test review locator, subject index, and instructions on using Mental Measurements Yearbook (MMY).