I like Captain Duck who has a bunch of tutorials and Lets Plays along with a soothing Dutch accent. http://www.youtube.com/user/captnduck

To get a great flavour of dwarf fortress in a longer written form. You can't go wrong with boatmurdered, which is a game where each player took a year (I think) of playing the fortress and then handed on to the next player to pick up the pieces and carry on. http://lparchive.org/Dwarf-Fortress-Boatmurdered/