how do you set keyframes on two diferent objects to "single user"?

i made a character and put in the rig added a keyframe and then duplicated it all. now when i’m trying to animate both characters move in the same way. someone on blender artists told me that i have to set the keyframes to single user in the IPO curve editor but i couldn’t find anything that said that. can anyone tell me how to do it?:o