CK-12 Foundation
Ck 12: Earth Science: Formation of the Moon
[Free Registration/Login may be required to access all resource tools.] How the moon was formed.
Australian Broadcasting Corporation
Australian Broadcasting Corporation: News in Science: Moon Over 4.5 Billion Years Old
From ABC News in Science, Larry O'Hanlon's article uses research connected to the element tungsten-182 found on the Moon to develop theories as to the age of the Moon and the formation of the Moon.
University of Wisconsin
The Why Files: Cosmic Consummation
After a dramatic introduction to the "Love affair," between Earth and Theia, this site gives support to the claim that the moon was created by a collision between these two planets. Also contains a brief bibliography.