From Interweave:

These handy little cases, designed to hold your cell phone and music player, are quick to make. They require a little bit of construction, still done with crochet. Embroidery is only a suggestion. Keep them in your purse or tote or on yourself with the optional straps.

Sizes and Yarn:
Cell phone: 3.5” x 6”
Music player: 3” x 4.5”
Any of these cases can be made with one skein each of two colors.

Also needed:
Large snaps, size 4 (one for each case)
Sewing needle and thread for snaps
Safety pins
Yarn needle for working in ends and embroidery
Small piece of sew-on Velcro for music case
1 set of .75” (2cm) D rings for cell phone case, optional