So my mom has an iPhone 3G currently and we are getting an iPhone 4 off craigslist tonight. My question is...given she is using the 3G which has a larger sim than the 4, can we simply change her to use the 4 with all her same contacts, emails, etc? Will I have to engage in "sim cutting"? Also, FWIW, she does have the $30 unlimited ATT data plan with the 3G, and we would be willing to continue that commitment. Thanks for the help!