The first place to start, if you want to learn more, is the collection of websites listed in the link boxes on this page. The best are the N.S. Gill's pages on the Ancient History site from About, the Perseus Project, the Powerhouse Museum, and the Deutsche Archäologische Institut (DAI). Interesting stuff can also be found at the Greek government pages, and the page at Archaeology magazine has a lot of cool sidebars on the history of the Olympic Games.
For this article, I also relied on classic texts, none of which, I am very sorry to say, are in press at the moment:
Ernst Curtius and Friedrich Adler. 1887-1897, five volumes. Die Ergebnisse der von dem Deutschen Reich veranstalten Ausgrabungen. Berlin. This is the classic excavation report from Curtius's 1875-1881 excavations.
E. Norman Gardiner. 1925. Olympia: Its History and Remains. Oxford at the Clarendon Press. This book is the first English discussion of both Curtius and Dorpfeld's excavations at Olympia; and an absolute must-have classic.
Heinz Schobel. 1965. The Ancient Olympic Games. D. Van Nostrand Company, Inc., Princeton, NJ. Written at the time of the Tokyo Olympics, this book attempts to set the history of the modern games in context with the ancient games; and is a little too warm and fuzzy for my taste.
There are some new books out that I have not seen yet, but look intriguing:
David Kennet, 2001. Olympia: Warrior Athletes of Ancient Greece
Ulrich Sinn, 2001. Olympia: Cult, Sport, and Ancient Festival.
Cooper C. Graham, 2000. Leni Riefenstahl and Olympia
This last book must refer to the movie about Olympia by the nasty Nazi director Leni Riefenstahl which, wouldn't you know? Is still available.
Leni Riefenstahl. 1936 Olympia, Parts 1 and 2. This movie was commissioned by Hitler before World War II and I can only imagine what's in it.

