This package implements a fast and precise solution for the two-bone inverse kinematic problem in 2D.
Take a look at webplayer demo to get an idea. (source included in the package)
It allows you to animate target positions instead of animating each limb individually, or you can make characters reach objects in the game. Look at the demos.
Also works with Smooth Moves animations
Easy to use for non programmers
Full source code included
Cute character and stickman included