Mirror joints and pole vectors

In order to create the right leg, I decided to mirror the joints in the left, rather than just reconstruct the whole thing from scratch.  I did this by selecting the entire set of joints from the hip; and then selecting 'Mirror Joint' from the Skeleton menu.

I reflected the joints on the YZ axis.  There was also an automated option of replacing a word with another, meaning that with this new leg, I could instantly replace every occurrence of the word left with the word, right.

Next, I mirrored the reverse control, using the same method.  I added each set of controls to its own layer.

After this was done, I created a curve around the left foot which would serve as the Foot Control; I added another attribute called a Foot Roll, which would come in useful later.  I altered the shape of the Foot Control, so that it had the same outline as the foot itself.  I then duplicated this and flipped it around to the right foot.

The last thing that I shall mention in this post are the locators; they were made by creating curves shaped like the letters l and r.  I moved these to the left and right legs and then constrained them as pole vectors to the IK handles in the legs.  They can now control the orientation of the knees.