I kinda know how to make characters walk, using this tutorial: http://www.youtube.com/watch?v=yxxGDJspptQ
It shows how to make them walk sidewards, but how do I make it walk to the front?
(take for example the character liz_front, because all of the characters are 2D you can only move their legs right and left, but to walk you need to move them back and forward).
Since there isn't a way to move a bone in the Z axis like you would need to make a character walk to the camera, you could simulate the walk using the bone scale tool to make one leg slightly smaller than the other as things look smaller the further away they are. Each bone should be scaled to achieve the best look,( the foot be furthest should be smallest then the shin being the next smallest then the thigh). Then return them to original size while scaling the other leg. Add slight bone translations to the foot outward when the leg is "foward" and straight when the leg is back to simulate the step. Repeat this for the arms as well as most people swing their arms slightly as they walk. Do small translations on the shoulders and hips to match the step.Finally scale the whole character to simulate them coming towards the camera. The size difference between the two positions can be used to do a walk or a run. Small differences=walk,bigger for a run.
Two excellent references are Preston Blair and "The Animator's Survival Kit", a book by Richard Williams. Both sources show breakdown drawings for characters walking towards the camera.
You can't have everything. Where would you put it?