It's a lot easier than it sounds... I really hope the pictures load!
1 pair size 4 little boy briefs
1 pkg bias binding. (I used 1/4 inch. I recomend using 1/2 inch or something wider than 1/4 inch because 1/4 inch does not look very awesome.)
1/4 yard 45'' coordinating cotton/cotton blend print or solid
less than 1/4 yard 20 gauge clear plastic (if you want an ID pocket)
1/4 yard 24'' craft-weight fusible interfacing (or more)
matching thread (match to bias tape)
Here's the plan:
1. Begin by using a seam ripper to remove the waistband. Be careful around the tag.
2. Rip the seams around the legs as well. Mine were serged around the crotch seam... Don't worry about that. I left them dangling.
3. Time to cut out the pieces. I used 4.5 inch x 8 inch rectangles. Cut one out of the front of the undies and one from the back. Also cut 3 out of fusible craft-weight interfacing (heavy weight washable) and 4 out of a coordinating cotton or cotton blend solid (or print if you wanna get crazy with it, you wild thing you.)
4. Iron the interfacing... One rectangle onto the back of both underwear pieces, and one onto a solid cotton piece. Ironing the non-stretchy interfacing to knit underwear is a little frustrating, so don't stretch it too much, keep trying, and have a little extra interfacing on hand. If you lay the fly out flat (like it would be normally), you can make it into a pocket.
5. Customize two of the blue rectangle (one interfaced, one plain) with pockets, and ID holder, credit card pockets, whatever. The interfaced one will be the front half of the money pocket. The non-interfaced one will be on the other side of the top flap. I recommend doing a big old change pocket on the non-interfaced, and an ID holder, credit card slots, etc. on the interfaced one.
6. Prepare to be confused: Sew the all the inside pieces together and all the outside pieces together. Hopefully you can see in the picture that the inside pieces are: plain solid, plain solid, upside-down uninterfaced customized piece. The outside pieces go front of undies right side up, back of undies right side up, upside-down interfaced customized piece.
7. Now turn that left column from the picture above upside down (don't flip it over, just turn it twice) and zigzag or serge around all the edges, attaching the insides to the outsides, RIGHT SIDES OUT. That means front of undies right side up attaches to uninterfaced customized piece right side up. If you do that right, the back of the undies piece will be sewn to a plain piece, and the upside down customized interfaced piece will be sewn to a plain piece. This is easier than it sounds. I just had the left piece upside down in the above picture. Sorry. Holy cow I'm bad at tutorials. Moving on.
8. Bias bind that bad boy all around the edges. Sorry about the dirty socks.
9. Fold the "front of money pocket" (see cheap little paint illustration at top) up to the "back of money pocket" and whip stitch both sides to make the main money pocket.http://img378.imageshack.us/img378/3917/picture8583ek.jpg
10. Yay! You're through!http://img378.imageshack.us/img378/3569/picture8697yy.jpg