matchBox...

No, not the cars, though they were pretty sweet when I was a kid...:) This is a sweet looking mel scipt. A buddy from work pointed me to it and I'm putting it here so I don't lose the link:) Here's what it says of itself:

MatchBox is the result of an effort to develop a universal character flipper that will work with any rig, every time. While animating a walk cycle, poses will be mirror images for the opposite stride. Even though the thought process has been completed for posing the first step, it’s a time consuming process to match the pose on the opposite stride. Match box allows you to quickly reverse and match the poses for a complete cycle. If the starting or ending pose of a cycle needs to change, the leading or ending foot may change as well, requiring reposing of the entire walk sequence. While some tools exist for flipping animation data across an axis, it becomes very difficult if the character is turning a corner or walking on an arbitrary angle.