Something

MovieClip.prototype.motion = function(variable, target, speed) {
	if (this[variable] != target) {
		if (!this.broadcastMessage) {
			AsBroadcaster.initialize(this);
		}
		this.onEnterFrame = function() {
			dif = target-this[variable];
			if (Math.abs(dif)>.5) {
				this[variable] += dif/speed;
			} else {
				this[variable] = target;
				this.broadcastMessage("ready");
				delete this.onEnterFrame;
			}
		};
	}
};