Has anyone tried an app called "Power Flower" Magic Battery Booster? The developer claims to be able to "calibrate" the iPhone battery to deliver longer battery life. Let's just say that I'm skeptical.
I've read a review (sorry, but can't remember where!) which indicated it was a complete waste of time!
The only to get the best out of your battery and calibrate it is to do as recommended by Apple. Namely, once a month, allow the battery to completely run down (until the iPhone shuts itself off) and then completely recharge.