One $100 GPU can mine at the level of about 700 high end smartphones.
A mobile mining 24/7 would produce about one penny ($0.01) of bitcoins per week.
Real miners mine by head! I'm currently on round 1 of the first round of sha256. Unfortunately I keep getting new work before I can finish so I have to restart... will have to find a shortcut.
^this, mining by hand can be a little more profitable than a smart phone, here you have some guidance https://bitcointalksearch.org/topic/manual-mining-56343 if you decide to take a shot at it
I loled at the mentioned thread, hilarious.