Massachusetts Institute of Technology
Mit: Internet Classics Archive: Works by Plato
A library entry with translations of many works by Plato, including commentary and discussion of each.
Other
Plato and His Dialogues: List of Plato's Works
This list of works by Plato such as The Republic also features links to e-texts in English translation.
University of St. Andrews (UK)
University of St. Andrews: Theodorus of Cyrene
A look at the life of Theodorus, who was Plato and Theaetetus' mathematics tutor. You can also learn about other Greek mathematicians from this website.
University of St. Andrews (UK)
University of St. Andrews: Theaetetus of Athens
Much of Theaetetus' life is unknown, but you will find he impacted mathematics and his fellow mathematicians greatly.