Here's one from sister Kate - no video to go with it but wait for a few and pics of Kate start to scroll. I am in love with her btw. I Courted a Sailor - Kate Rusby
Here are some good ones by Great Big Sea, Gaelic Storm and Stan Rogers! If you haven't used Grooveshark before it is nice to make your own playlists online, but beware if you have a slow connection.
P.S. If this link doesn't work let me know. I tried testing it by logging out of my account (free to setup), and it appeared to still work.