This is far from the definitive guide to updating your iOS devices, but it’s user-friendly with lots of pictures!
In this guide you’ll find several different ways to back up important files, how to transfer purchases to your machine, and how to create an encrypted back-up. While every update is different, I tried to include as many scenarios as I could in here without becoming completely overwhelming. It’s not a clean process by any stretch, but if you couple of hours to spare and follow these steps, you’re important files will be safe.
Good luck and happy updates!!
Eanes iOS5 Update Guide