Encyclopedia Mythica is a great online resource for, well, myth, including the gular Authurian, Grecian, and Egyptian, but also some more esoteric interests: Basque, Korean, Persian, etc.
This site is less scholarly and much more specific, but interesting for that; it's a complete listing of every single woman, human or immortal, ever mentioned in ancient Greek myth. (She's got a much smaller section on men.) She lists them alphabetically by name, along with an entry about their story, symbolism, who they were related to, etc. Then tops of the lot with a bunch of related paintings/scultpures/photographs.