The latest edition of the MLA guide is also available in the reference section of Durick Library. A more specific starting place for theatre research, particularly if you're looking at current professional theatre, can be found at Theatre Central . A vital collection of images, texts, and references relating to classical Greek studies can be found at the Perseus Project based at Tufts University. This site also includes an excellent overview of Greek history and an encyclopedia of Greek words and names. If mythology is giving you grief, you might take a look at this site on folklore and mythology and its links to other sites.
Greek tragedy is far from dead.