A core features of iOS 5 was severing the link to the computer, finally iOS devices don’t need a connection to iTunes to get things done.
Well your first chance to give it a go is here!
If you’re like me, you’ve read about it but not too sure how to actually do it, so here goes.
Go to System Settings, then in general and their’s an option near the top Software Update. Pretty easy but I still had to google it 
Then it’s very straight forward, check out the two screen shots below to see what it looks like, click on each for a larger view.
Navigate to the software update page
Click Download and Install - easy!
i can’t see ‘software upates’. im using ipod 3g 4.3.5
Hi there,
You need to be running at least iOS 5.0 to use this. So upgrade using the old method (i.e. via iTunes) then once you’re on version 5 you can follow the method outlined in this post from then on.
Peter