Well, this is what my GF faced when she got her 3GS.
The phone battery lifespan was seriously pathetic.
It drops like 10% every hour on standby.
We searched around the net for a solution and we did this.
Restore the iPhone as new.
Disable Notification.
Now the battery life seems to be normal.
The firmware seems to be the problematic.
Camera malfunction is being reported too on apple forum.

This post has been edited by crazy25kid: Aug 12 2009, 02:47 PM