I met David at JuliaCon a couple weeks ago -- he's a physics professor at the National University of Mexico and a charming interlocutor. I haven't made it through this (4-hour) tutorial myself, but the word among the core developers on the Julia mailing list is that it is very, very good.
David did a phenomenal job with this tutorial and I highly recommend this as a starting point for anyone who wants a good, digestible (and entertaining) intro to Julia.
While I thought this language was tailored for numerical computations, I've heard of people using it as a fast general purpose language too for those that want c like performance but don't want to write c
As others have posted, the 3-hour second part is here: http://pyvideo.org/video/2753/introduction-to-julia-part-2