I'm sure Dan knows the immediate answer to this, but just in case someone wants to try beating him to the punch, here's what I'm trying to achieve:
I need a simple way of moving a layer on an angle. Essentially, I'd like to have two sliders on a footage layer: one for X-position, and one for angle. As I set keyframes and animate the X-position of a layer, I would like the Y-position to automatically increase/decrease in a way that makes the layer appear to be sliding on the defined angle. I've tried rigging my own solution by using the tangent of a given angle, but that didn't seem to work.