here is something i use for my itouch, it has survived the rain so far.
i just wrap the arm band around the foam bmw thing on the handle bars.
(Monster Cable iEZClick Wireless Remote for Apple iPod) ebay has them cheap.
just have to watch out for the volume going all the way up or down some times when using it. iv just started talking into my autocom to make the volume quieter till i get the volume back down.
but works pretty good.