This guide will show you how to access the battery of the Samsung Galaxy S so that you may remove and/or replace it.
To remove the back case of the Samsung Galaxy S, you may need a spudger.
Identify the slit which is at the bottom edge of the phone.
Insert the edge of the spudger into the slit and use it to pry the back case off of the phone.
Insert the spudger into the space between the battery and the phone and pry the battery out as you slide it along the underside the battery.