i recently read this article that says keepng your phone on your side actually reduces your hip bone density.. so i keep mine in my pocket!
Cell phones may reduce hip bone density
Be careful with any of these "statistics". It's pretty easy to skew the numbers to represent what you want them to be. The media does this ALL the time to scare the general public.
Anyways, I usually keep my phone on my hip because the lint from my pocket was messing everything up.