Here's a pouch I finished yesterday for my Nintendo DS lite. I do own a hardscale case for it, but I find it really unpractical for just 'usual' carrying in my bag. so I made this one instead. No sewing machine needed!!
cut your fabric and lining fabric in desired measurements. Pin them down together good sides faced to each other.
Sew around the sides, leaving a small gap. Turn inside out, fill it with cotton balls (I rolled them out), and sew it close. The last part won't look that great, but it doesn't matter if, when sewing the two pieces together, you'll make sure that the ugly part is at the side you won't see.
Repeat this for the second part. Then, again with the good sides facing each other, sew the two parts together stitching 3 sides together and leaving one of the long areas open. Turn inside out and tadah!!! A nice stuffed cozy/pouch for your DS.