University Press
University Press: Architecture in Ancient Greece
A good basic reference on the main types of temple architecture in ancient Greece, including Doric, Ionic, and Corinthian. Also includes information on architecture, the Parthenon, and sculpture in ancient Greece, with accompanying links...
University of Oxford (UK)
Beazley Archive: Erechtheion
Illustrated dictionary definition of the famous temple Erechtheion. Describes the temple's architecture, significance behind building the temple, and the location the temple was built.
The British Museum
British Museum: Highlights of the Collection: Caryatid From the Erechtheion
View a highlight from the museum's collection of a caryatid, one of the original six column supports removed from the Erechtheum, an ancient Greek temple located on the Acropolis.
Boston College
Digital Archive of Architecture: Ionic Pillar
Here is a photo of an ionic column in the Erechtheum.