I'm just beginning to learn how to animate a walk cycle and have jointed a figure and animated a single step in place. I've then set the keyframes to repeat from the timeline window and moved the figure forward. But I don't seem able to get the figure's step to match the speed of movement correctly and as a result he slides around.
The first step (no pun intended) is to make sure that you set linear keyframes for the feet that are on the ground. Then you have to figure out the distance of each stride (how far you move one foot back + how far you move the other foot forward) and move the master controller forward that distance for each step. So if each step takes 10 frames and the stride distance is 1000, go to frame 100 (10 frames * time 10 steps) and keyframe the master controller at 10,000 on the axis in which he's moving (1000 stride length * 10 strides). The master controller position keys also have to be linear.