I gave my old iphone 3 to my friend and have realised he is receiving my imessages that i receive on my new iphone 4S. Please can you tell me how i stop this so he stops received my messages?
Try doing this on the iPhone 3:
You should have reset your phone before passing it to someone else. I'd suggest asking your friend to reset your phone by going to:
Settings > General > Reset > Erase All Content and Settings
This will erase all your personal content and settings from the device.