Unity Script Reference:

static function FreeRotateHandle(rotation: Quaternion, position: Vector3, size: float): Quaternion;

Parameters

rotation	Orientation of the handle.
position	Center of the handle in 3D space.
size	The size of the handle. Note: Use HandleUtility.GetHandleSize where you might want to have constant screen-sized handles.

Description

Make an unconstrained rotation handle.

The handle can rotate freely on all axes.

FreeRotate handle seen in the Scene View.

	// Create a simple rotate handle (half scale) on the 
	// target object that lets you freely rotate
	// the Object Without having to select the "Rotate" button
	
	@CustomEditor (FreeRotate)
	class FreeRotateHandleJS extends Editor {
		function OnSceneGUI () {
	        target.rot = Handles.FreeRotateHandle(target.rot, target.transform.position, 0.5);
	        if (GUI.changed)
	            EditorUtility.SetDirty (target);
	    }
	}

And the script attached to this Handle:

	@script ExecuteInEditMode()
	
	var rot : Quaternion = Quaternion.identity;
	
	function Update () {
		transform.rotation = rot;
	}