It is possible that internet access will be available, depending on your service provider. However, if you unlock the iPhone in a country where the EULA prohibits you from doing so, and the internet does not work, you're pretty much out of luck, since unlocking the iPhone completely voids its warranty.
Yes it will
No, the cell phones have to be from the same service provider in order for them to work.
No sorry the Iphone uses a different type network than the Nextel service.
Yes it will. I have mine with Centennials service
A celluar provider that offer the Apple Iphone 4S with is Att&T. You can purchase the Iphone full price and have it unlocked allowing it to be used through a service provider. These unlocked devices do not work on CDMA carriers such as verizon or sprint. You will then have to contact the service provider to have the phone connected to the network and set up the features you would like on the phone.
Contact your service provider and they should be able to transfer your Pay and go contract to your sim and cancel your Contract account.
Yes. The iPhone 5 works well on European cellular bandwidths.
Call your service provider and ask for a diagnostic on the problem, if that doesn't work, consider switching to a new service provider.
Via wifi. You will need to download a texting app
yes the games will work without interent as long as you have downloaded them onto your homescreen or have an app
when a phone is unlocked it means andy service provider is going to be able to be used in that phone. in other words, virgin mobile should work