iOS 4.2 will come out in November 2010
New iPads that come with iOS 5 do not require a computer to setup your iPad. If it's older than iOS 5 then yes you need a computer for setup.
Instead of waiting for jailbreakme, if you really want to jailbreak you can use redsnOw it jailbreaks iOS 5. But I'm going to wait for jailbreakme to jailbreak iOS 5 because they are the easiest to use and it is pretty much impossible to mess it upp
The apple iOS 5 update IS OUT NOW
Yes, Apple iOS 5 is free.
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.