Lets say I bought my iPhone last year and I want the iPhone 3G. Can I give my old iPhone to my sister or sell it on eBay?
No, once an existing iPhone user activates service for an iPhone 3G, their first-generation handset will be unusable as a phone. You won’t be able to replace it with another AT&T SIM card and use it to make calls. This also means that you can’t buy an old iPhone on eBay and expect to activate it on AT&T’s network. However, you can use it as a media player and a Wi-Fi device for browsing the Web. This is wrong, you can hand down iPhones, and buy them over ebay etc. You will need to get a valid SIM, either one that comes with the phone or from AT&T. It is possible. CNET please correct this part of the article.
No, once an existing iPhone user activates service for an iPhone 3G, their first-generation handset will be unusable as a phone. You won’t be able to replace it with another AT&T SIM card and use it to make calls. This also means that you can’t buy an old iPhone on eBay and expect to activate it on AT&T’s network. However, you can use it as a media player and a Wi-Fi device for browsing the Web.