This summer, there's an Introduction to Irish Myth and Folklore being offered by Harvard's Extension Dept. It's a bit of money, but it's online.
I can't afford it, but found out last night that if you click on the "website" link, you get some really cool stuff. Course documents include links to Balor and Gaibhde the Smith (which you can print up!), The Second Battle of Mag Tuired (ditto), etc. Good reading. Also, The Coop, Harvard's bookstore has an online ordering for their textbooks. You don't need to be a student to buy books! (and you can get them used)