If you recently updated your iPhone 4 to OS 4.3 then you might have observed that the battery life has reduced a little bit. I updated my iPhone 4 to OS 4.3 two days back and realized that the battery started draining out pretty faster than it did before. This is simply because of the built in ping function as reported by several users. Ping uses its own framework resulting in more processor usage and network traffic. Apparently, this is due to a bug in the framework which causes ghost processes.
The simple and straight forward solution to this problem is to disable the ping feature. You can do this by going to Settings> General >Restrictions and then turn off ping.
If this doesn’t work then you may do a factory restore. This will restore your iPhone back to the original version.
If nothing works, you may try going to Settings/Mail, Contacts, Calendar, click on the Exchange account name and turn off the 3 switches. Once done, reboot the phone and then turn the 3 switches back on. If you aren’t using these features then turning them off permanently is a good choice.