Now, while the zipper is still easily manueverable, you will want to trim the "open" end of the zipper to about 1 inch from the end of the fabric. Fold back this zipper at a slight angle, and stitch/tack it in place securely. This picture should help explain what I mean.
The picture shows the zipper attached, but that's only because I didn't take a picture before attaching it.
The next step is to pin your zipper piece to the bag. Look at this picture while I explain.
You want to center this zipper fabric in the center of your bag. You will have your bag inside out, and the zipper fabric will be on the "right" side of the bag as you see here. The "inside" of the bag is the greenish/tan.. an the "outside" is the purple. You will have about 1 1/2 inches from the end of the zipper fabric to the seam on both ends. Pin this well.
In the picture below, you see the 2nd line of stitching, which is right on the edge of the fold of the binding. This should be 1/4 " away from your first line of stitching.
Turn your bag right side out. Are you ready? There is your finished bag! :) Isn't it magnificant! :)