Zane,

I provided a link to some instructions I gave last year in your other post.

There is also a method of cutting the rootball with a knife or saw 2" up from the bottom and 2-3" from each side. Many will tell you once you do this, you can just backfill the container with new growing mix. I would recommend removing all of the soil from the roots, regardless of the method you use.

Once you have the tree bare-rooted, inspect the roots for RKN or other bugs living in the root zone. Then, prune off any damaged roots and a few of the thickest roots. Next, cut the remaining roots back so when you place your tree back into the container, they are about 2" from the perimeter. BEFORE YOU CUT TO LENGTH: Visualize the roots cut back to length. If it seems like you are going to have an imbalance between the roots and the top of the tree (not enough roots to support the top of the tree), it is time to move up to a larger container, and you will want to prune to length for the new container. Then pot up the tree.

Some notes which may benefit you:
Water the container the day before you bare-root.
Use a bamboo chopstick to remove the soil from the roots and to work the roots back into soil when you repot.
Do not let the roots dry out. When you are not working on the roots (e.g. preparing the container, eating lunch, etc.) soak the root zone in water.
Don't worry too much. Figs are resilient and will bounce back from some abuse.

good luck,
~james