You need to be plugged into iTunes to update the latest software and it isn't always recommended for those that are Jailbroken.
Yes but your iphone has to be jailbroken and have Cydia.
if you can access itunes on your phone you can download music through there ,but if not you can use itunes on your computer , download them through there and synchronise your iphone with your computer.
You ll get for not jailbroken . Factory unlock will sell for more.
Im not sure what you mean by installer but I assume your talking about apps. If you want to install apps you can download them from the app store and it will automatically install.Or you can download on itunes and sync to iPhone. If you have jailbroken you need to install 'installous' on cydia by adding hackulous as a source . Search how to install installous. For a normal iPhone that hasn't been jailbroken you don't need a extra program. But for jailbroken you need installous. I work for apple California i would know Also don't jailbreak it messes up your iPhone slows it down and voids your warranty.
as far as i know, only 1 phone can, a Jailbroken iPhone with the app mxTube
You dont
You may download games straight from your iPhone using the App Store. You may also download games from your computer using iTunes.
Download iTunes
You can get free ringtones for a non jailbroken iPhone 4, 16gb online at mobyware.net.
No, you can even unlock the iPhone when Jailbroken.
Yes you can.If you have an jailbroken iphone you can get it for free
most people don't supply iphones that are jailbroken luckily you can do it both on mac OS x and windows operating systems you might have some trouble on Linux just check a youtube tutorial