If you had gotten a text from a person deceased then that would have been freaky.
However just incase i'd recomend using ouija board to see if you can find anything out, in fact there might be an ouija board app that could utilize the iphone's touch screen, and maybe flick through the ghostly responces in cover flow. Zippy.
I will thx, I saw this ghost show, and this girl said her computer was turning on and off and doing weird things in her haunted house, AND IT WAS AN iMAC!
I SAW IT!