From iPhone 4 and beyond you can use simple software to unlock your phone. The 3GS is not able to unlock your phone unless you buy a special SIM card or take it to a different carrier
no, they are completely different designs
no why do you think its called trading in?
No they are two different types of outer casing on the iPhones
iOS 5 will be compatible with iPhone 3GS as well as iPhone 4.
Yes, you can put an iPhone camera in an iPhone 3GS provided you have the required skills.
Yes, the 3G and the 3GS are a different shape than the 4 and 4S.
iPhone 3GS. Then the iPhone 4 and then the iPhone 4S.
yes
yes , uu can .
No. The only iPhone that has the ability to FaceTime is the iPhone 4.
iPhone 4 ,however my father has the iPhone 3GS which is quite good.