Following up on its 2006 Sleeves, which were noteworthy mostly for their simplicity and low pricing, iStyles has released its 2007 Sleeve Collection, consisting of 13 different fabrics that have been transformed into $10 iPod-sized pouches. Most of the 2007 Sleeves now include a slit-styled side pocket large enough for earphones or credit cards, and a larger microfiber-lined central pocket designed either to fit an iPod, or the smaller nanos and shuffles.…