Correct wrong email address used to set up iCloud account
First before doing ANYTHING, make sure to turn off find my iPhone.

Then go to https://appleid.apple.com/ and change your appleid.  

Then there will be a number of places you need to log out on your phone and log back in with the correct ID. iCloud, iMessage, Facetime, game center, app store/iTunes to name most.

Then turn FindMyIphone back on.