Rigging your character is one of the most complex tasks to accomplish in Blender. And there is nothing like a good tutorial to help you along.
And thats just what Yogyog has created. A detailed yet concise walkthrough of rigging a leg for a standard human style character.
After a lot of experimentation I came up with this rather good leg rig, so I thought I'd share it with you. This tutorial assumes you know the basic Blender interface, but little else. This a good tutorial to learn about bones and armatures. If you're an experienced Blenderer, this is still a good foot-rig: you can just follow the pictures and the orange text.
Find the tutorial here.