You can turn off iMessage in Settings -> Messages -> iMessage (turn slider to off). At that point you will no longer be able to send iMessage's and you will no

You can turn off iMessage in Settings -> Messages -> iMessage (turn slider to off). At that point you will no longer be able to send iMessage's and you will no longer be able to receive them. The thing is that the iPhone when first activated reads the number from the SIM card/carrier and sets that up as an iMessage address. Apple is never pinged when you move your number away from your carrier unless you re-activate your phone with a different SIM card (I still am not happy you can't activate the phone without having a carrier plan ... yay Jailbreaks!). In the article he mentions unregistering his devices/phone from Apple's website, that will work until the next time that his phone pings the iMessage server and re-registers itself (disable iMessage first ... it unregisters the device). I personally would say that is working as designed, if I unregister all of my devices, if I turn one on to use for texting it should re-register itself automatically.