Yes, Apple iOS 5 is free.
The apple iOS 5 update IS OUT NOW
You cannot. If you buy a new iPod or iPad or iPhone, it comes in iOS 4.3.3 and you have a choice to update to IOS 5 or not.
The apple iOS 5 update IS OUT NOW
Yes you can.
You can update it to iOS 5 the same way you update it to any other iOS version. The 4th generation (and indeed the 3rd generation) iPod Touch can be updated to iOS 5.
iOS 5.1 untethered jailbreak
Yes, when iOS 6 comes out it will be free of charge, just like iOS 5 and iOS 4 were.
Any iPhone, iPod touch, or iPad that is using iOS 5.
Connection to iCloud will be included with iOS 5 when it is released.
The iPhone 5 will run iOS 6 or iOS 7.
By installing them and opening them. iOS has backward compatibility.