Algorithm for orientation of a 2d vector?

Hey; I was wondering if there is a simple algorithm that takes an x and y value (the values of the vector), and returns the angle between north and the vector, clockwise? All that I learned in trig class back in school has left me, and Google isn't giving me anything useful.

>>14
I am awed by your knowledge of linear algebra.
Er, this is something that anyone who took trig should know. And it's wrong anyway. He's mixed it up with sine.