Gauge isn't hugely important here - and the pattern is very easy to size up or down if you want to make a cozy for another device.
Yarn used for examples: Sirdar Denim Chunky Hook: 5.0mm
Other items: Tapestry needle, button
Ch 20, and without twisting ch, join with sl st in first ch. Check that this loop fits around the circumference of your iPod. Add or remove ch as appropriate. You want a snug fit.
Row 1: Ch 1, 1 sc in each ch around, sl st in first sc to join - 20 sc.
Rows 2 - 16 : Ch 1, sc in each st around, sl st in first sc to join - 20 sc.
Row 17: Sl st in first 6 stitches. 1 sc in each of next 9 st - 9 sc. Ch 1. Turn.
Rows 18-20: Sc in each stitch along - 9sc. Ch 1. Turn.
Row 21: Sc in first 3 st, ch 3, sk 3, ch 3. Ch 1. Turn.
Row 22: Sc in each st along, including the 3 ch - 9 sc. Ch 1. Turn.
Row 23: Sc in each stitch along - 9 Sc. Ch 1.
Row 24: Sc in each stitch along - 9 Sc. Fasten off and weave in end.
Starting row: Ch 9. Row 1: Sc in 2nd stitch from hook. Sc in each stitch along - 8 sc. Ch 1. Weave in tail as you go.
Rows 2-12: Sc in each stitch along - 8 sc. Ch 1.
Row 13: Sc in each stitch along - 8 sc. Fasten off, leaving a 12 inch tail.
Attach the pocket using the tail, to the cozy underneath the flap (to what will be the back of the cozy). Tie off, and weave in ends.
Turn the cozy inside out. Using the tail at the bottom, stitch the bottom seams together.
Turn the right way out. Tie off and weave in tail. Weave in any remaining ends. Affix button.
The flap is half as tall as the cozy itself, so if your cozy is 20 rows tall, your flap needs to be 10 tall. The flap is then also half as wide, so if your cozy is 10 stitches wide, your flap needs to be 5 stitches wide.
For the buttonhole, on that row just ensure that you divide the length of your row into thirds - then sc one third, ch and sk another, then sc the last third. In the event of the row not being an exact multiple of 3, make the button hole wider if it is 3+1, or make the 2 side rows wider if 3+2. E.g. for a row of 11, you would sc 4, ch 3, sk 3, sc 4. For a row of 10 you would sc 3, ch 4, sk 4, sc 3.
On row 17 of the cozy you don't HAVE to do the slip stitches, but this ensures that the seam will then be at the back of the cozy and will be covered up by the pocket. Only a small change, but one I think is worth making.
Feel free to make items from this patten and donate them, or give them to friends and family, however I would ask that you don't sell any items made from this pattern without asking first :) Thanks!