I'm going to write a script that will be a great tool for animators but I could use a little guidance. Here's what I'm trying to do:

Imagine you're animating a character. Now, you're on frame 100 and you decide you want to turn the character's head. So, you turn its head BUT you are obligated to set a keyframe before frame 100 to serve as the start of the turn. Instead of going back in the timeline, wouldn't it be great if you could hit a button on a gui that would automatically set the keyframe for you. The gui could have a slider that allows you to set the number of frames back in time that the keyframe would be set. There could also be check boxes so you could tell it to set Trans X,Y,Z or Rot X,Y,Z.

I'm not trying to get anyone to write this script for me but if someone could point me toward the MEL commands that would most useful for this, I'd appreciate it. I'm not worried about the gui. I'm more concerned with the commands for going back in time and setting the keys.

Thanks a bunch!