I would sew a little strap to the inside of the suit the you could then hang the Ipod on.

Even easier wear a pocket T-shirt under the leathers and put the iPod in its pocket.

Some of these guys like to switch tracks while riding so that wouldn't work. I just put that sucker on random or create a really long playlist and roll with it. Or if you have a Zumo you can use the touch screen to change tracks but that's fookin dangerous as well.