You'll have to set up a grid. I think most programs have a configure grid option, and this grid doesn't show up when you save it. I normally set mine up 100x100 (on a picture base that is 400 width and 1100 long). Then you paste the ready pose of the guy into the first frame, then select the entire square that the guy's in. Then you copy/paste it into the square beside it, and then he doesn't move. You can then overlap animations for him onto that square.
I'm pretty sure this can be done with photoshop. if you don't have either of these programs just google GIMP.