There's an excellend tutorial for it over on Sew Mama Sew, but I sort of assembled it on the fly. Basically I cut a piece of muslin the size I wanted my outer panels to be then cut my purple/green/print rectangles a few inches taller than that. I sewed the print and solid together for each side using great big stitches, and basted along the ends. Then I gathered up the two ends and the middle, pinned them to the muslin and stitched around the edge using a smaller-than-usual seam allowance (somewhere between 1/8th and 1/4 inch). I used a decorative stitch to stitch down the gathers in the middle so they didn't flop about and then did the pouch assembly just like usual.
Given my love of color, I couldn't just use the same thing on both sides, so I used a green tone-on-tone floral with the print on one side and a purple tone-on-tone plaid with the print on the other side. I like the way it came out-and it wasn't any harder to construct than a regular pouch!
The next little project I made was a needle case. This time I did follow the tutorial over on Sew She Sews and it went swimmingly except that I assembled it upside down. Since I was making one for me and one for my mom, I actually assembled it upside down TWICE (go Shannon), and was much saddened to have to disassemble it. It was either that or have the nice quilted part on the back, or have it open on the left. Yuck. But in the end it all worked out well. And bonus- a completed project in a neutral color scheme! I did do all the quilting before I cut the pieces apart to make the two cases, I wish the quilting motifs had lined up a little better but there you have it.
Hope you enjoy!