If you check out your Sure-Fit Designs Pants Kit Master Patterns (Pants Back), you'll see a 'tear-drop' shaped Inseam Pocket pattern.
1. Copy the pattern on your tracing vellum. You don't need to add seam allowances since this particular pattern piece already has them incorporated.
2. On both the front and back pants patterns, mark the corresponding front and back side seam notches approximately 2" (5.1 cm) and 9" (23 cm) down from the waist edge on the side seam.
3. Sew one inseam pocket to the pants front side seam, and the other pocket piece to the pants back side seam between the notches as illustrated. Clip the seam allowance to the upper and lower notches.
4. Sew the front and back pants side seam together from the hem up to the lower pocket notch. Skip the pocket opening and then continue sewing from the upper notch to the waist edge.
5. With right sides together, sew the pocket pieces together around the curved edge.
For more pocket stability, the top of the pocket can be squared off and lengthened so that it could totally be sewn in to the waist edge. This of course, would be done during step 1 - the drawing stage.
Suited to be incorporated in either skirts of pants, these inseam pockets are simple and easy to draw and sew.