First....you'll get flamed on this board by all the people who profess to have superior intelligence and the proper "caring" attitude.....if you mention that you like to listen to music while you ride.
So, being such an idiot, like me, take a look at the velcro straps such as those used to hold pumps secure to a bicycle frame. I use that to attach my mp3 player to the stem on my bike. It's secure and easy to read and use. Also, for aero bars, I use the plastic straps to connect to the carrying case and hold it between the bars.....
Good luck and enjoy the tunes.
Oh, by the way, recent study by a large eastern college revealed that music increased the performance of the athletes involved by 15%....that's enough to win a lot of road races!