Jens Krause beat me to the punch. I had brightness added to Tweener AS3 and was adding contrast and saturation as needed on projects but it has already been done!

WS-Blog has added in special properties for Tweener for brightness, contrast and saturation which was the only part missing from the public version of Tweener. I am not sure of the file size with this addition (Tweener is around 9kb) but it is probably the same size with this in as brightness in my updated copy was the same. Adding special properties in Tweener is quite simple and not enormous amounts of script needed and when compressed in the swf it is very small.

There are other kits like TweenerFilterLite, Animation Package etc that do these right now but you have to wait no longer for these functions in Tweener itself which has quickly become many flash developers favorite in AS3 and since it is compatible with AS2 in the same syntax it makes animation in flash and the learning curve for that from AS2 to AS3 non existent for motion.

Jens has a sample demo, script samples and source on his blog.