You can't. The radio chips inside determine which version of iphone you have. It is impossible to change out the chips yourself.
They can be transferred from computer to the handset. They can also be downloaded to the handset.
No you may not get an iphone 4s without a contract in some countries. However you can get them without a contract in others. However, the cost of the handset becomes really expensive for up front costs on PAYG.
Firstly, AT&T is spelt with an '&' symbol. Secondly, if your purchased your iPhone from the online Apple Store, the handset will already be unlocked and you can use any service with the handset. However if you purchased the handset on a network service plan, you will need need to contact your service provider.
It is on the packaging that the iPhone is in or you can check the available memory via iTunes or the handset.
15 years
This will be for all location services on the handset.
You can't unless the handset is turned on.
You get the handset (iphone) Computer cord (for itunes) wall charger, manual and probably a screen cover xx
You need to go to settings and you will see the option to change your ringtone there, together with changing other tones for other functions on your handset.
Yes by not recharging the handset until it drains the battery.
It will depend on where you rent/purchase the handset from.
Yes as long as you have authorised the handset with the Mac.