I have a iPhone 4s that I use to use with Verizon and I've come across a few articles about being able to use a straight talk SIM card in a iPhone 4s but on AT&T and T-mobile networks. Does it matter if my cell use to be on the Verizon network or not ? I understand I will have to change some settings in the phone but just want to make sure it will work before I buy the tools and SIM card. Also if by any chance if someone has a link to a really good tutorial can you plz post the link. Thanks for any and all replies.