Pose estimation for rectangle in flash application

I'm working on a simple augmenter reality application and my question is:

Is there any simple algorithm or library out there that could help me to determine rotation and perspective of a plane where my test object (black rectangle) is located.

I basically grab a frame from webcam and then mark the corners of a test object. Now i know the position of every corner in camera focal plane and of course i also know the position of the corners of the test object on paper plane. What i want to know is what kind of rotations 开发者_运维问答I should make to reach the situation on the photo. In case of multiple paths, for me...any of them is suitable.

I plan to render some photos onto that plane (which I can't define at the moment) with Five3D AS3 library.

FlarManager (http://words.transmote.com/wp/flarmanager/) is what you're looking for. tutorial: http://gotoandlearn.com/play.php?id=114