Seriously, some of the ideas I found here are absurd. I hope you guys go to the gym and understands that you can't attach your wallet, PDA and other devices on your shoes while you take a round in the treadmill. It will give you a headache when you bent down and reach for your phone after a sweaty workout and also cause some serious imbalances on your feet - unless you own two similar phone and two straps OR you would like your other leg much more muscular than the other one.

Some of the designs such as the hand glove is ideal but not when one does the boxing work out. Also take note of the ability of such clothing gears to absorb or repel sweat, as it will be smelly and dirty in the long run.

Besides that, I usually use my cellphone to count the minutes that I have on the treadmill or as a tracker on the number of push ups or sit ups that I do - so these accessories should still allow functionality of the device.

I would vouch for the Arm strap if it doesn't require strapping in the arm after the workout. So my design submission would be similar except it'll be a bag that you can strap on the gym equipment. I will post my rough sketch tomorrow after a good night sleep.