Cornell University
Cornell University: Astronomy: The Phases of the Moon
This site from Cornell University provides great information on the different phases of the moon. As the Moon moves in its orbit around the Sun, our view of the side illuminated by the Sun changes. Furthermore, the rising and setting...
NASA
Nasa Star Child: What Are the Phases of the Moon?
This page provides basic information about the causes of the phases of the Moon. A good diagram shows the lit portion of the Moon as seen from Earth through one complete Lunar cycle.
Other
On Hiatus: The Moon
This commercial site [without any advertising] provides a diagram of the current illumination of the Moon, and the dates of the most recent and upcoming New, Quarter, and Full Moon phases. All dates and times are in universal Time, only.
Other
Introduction to Astronomy: The Motion of the Moon
This site provides a moving diagram of a Lunar eclipse, showing Earth's umbra and penumbra and the appearance of the Moon as it passes through these shadow regions.