battery issues

Hey guys I am using lithium ion 18650 cells in a parallel config for increased capacity. I want to know discharge voltage of this pack. And how do we know my cell pack has been discharged.
Also, what regulator IC should be used to provide constant 3.3V or 3V voltage from the cell utilizing the cell capacity to the maximum.

Your suggestions will be appreciated.

The Battery University website has lots of useful info.

...R

18650 cells have a minimum discharge voltage of 2.5 volts.

Jeff Nadrich