Alright, so I found this code somewhere on FK and I've converted it to AS3 and it seems to work correctly:
var startx:Number = mc.x;   // starting position
var endx:Number = stage.stageWidth - mc.width;    // ending position
var starty:Number = mc.y;   // starting altitude
var travel_height:Number = 600; // travel height
var duration:int = 3*1000;  // duration of travel in milliseconds
var startTime:Number = getTimer(); // starting time (now) in milliseconds

mc.addEventListener(Event.ENTER_FRAME, jump);

function jump(e:Event):void
	// convert current time to an animation ratio (r) from 0-1
	var r:Number = (getTimer()-startTime)/duration;
	// we will use 'r' to control everything in the animation
	// stop animating when we reach 1
	if (r >= 1)
		r = 1;
		mc.removeEventListener(Event.ENTER_FRAME, jump);
	// use r to determine horizontal coordinate
	mc.x = startx + r*(endx-startx);
	// use r as input to Math.sin() - scaling to 0-PI
	// using value of Sin to make vertical motion
	mc.y = starty - Math.sin(r*Math.PI)*travel_height;
This tweens a MovieClip from a starting point to an ending point following the curve of a parabolic function.

What I would like to do, is rotate the mc while moving it. Imagine a horse jumping over a ledge, when it starts its front legs are aimed upwards, but when landing, they will point downwards.

The MC I'd like to move will be a jumping animal of some kind, so the movement has to be spread out just right so it starts facing upwards, then levels when the function hits its top-most point and then start rotating downwards again.

Hope this makes sense