Recently canceled cell service for iPhone 3GS (iOS 6) but have still been using it to iMessage. Today I got a message from someone I didn't know apparently AT&T reassigned my phone number to someone else and both my phone and hers were receiving the messages. How do I have others iMessage me to my email address instead of phone number?
Go to the deregister page at:
You can also change the send as "caller ID" portion for sending new messages in the Settings App -> Messages -> Send & Receive -> Start new conversations from:
You might have some old conversations that end since you are now using your email for iMessage so send a new message to your friends if they won't know to try your email instead of your SMS going forward.
If you see your old phone number in Settings > Messages > Send & Recieve, you can reset this by turning iMessage off and on again