On EVERY one of your ios Apple devices (iPhones, iPads, iPod touch):
- Go to Settings
- Go to Messages
- Move slider to Off for iMessage
On EVERY Apple computer you own:
- In Finder or Searchlight search for "messages.app" to find the messages app
- Click on the message app ( it has a blue and white bubble icon )
- If you are signed out, sign in using your apple id
- Go to messages preferences
- Uncheck "you can be reached for messages at" next to your phone number
- Click "sign out" button at top right
- Quit iMessage