Quicksand provide an eye-pleasing shuffling animation effects like Mac apps and sorting and filter items with jQuery. At the very basic level, Quicksand replaces one collection of items with another. All you need to do is provide those two sets of items. The code you can be used for free.
Flashnest has introduced a nice flash version animated twitter bird for free. You have to register for download the twitter bird. It can be resize, available with four different colors and its only 7kb each. The best part about this twitter bird button is that you don’t have to open the FLA to specify your “Twitter Link”. You can do this through the embedding code. It is explained in the documentation file. If you would like to change the twitter bird’s color, then open the FLA file that is included with the download file.
Found some websites with lot of cool transition effects for flex. Right click to view the source and get it for use in your own applications.
Transition effects :
Zoom in & zoom out effects :
Bounce, expand & collapse effects :