It's better to make a back up with itunes before you jailbreak incase you have to restore it, then you'll have a fresh back up.

You don't need to restore it to it's factory settings, like the other user stated. Just make sure you updated your device through itunes and not OTA (Over the Air)

Lastly, you can find the jailbreak here [ Register or Signin to view external links. ]

You could read its "Important read me" section on the page

Goodluck!

Gubbins wrote

Cincinnati-Bengals wrote No need to restore unless you come into complications during the jailbreak. But definitely back it up either to the cloud or itunes on your pc/mac. BTW make sure your device has no passcode.

you can have a pass code. I did when I jail broke my phone?

Taken from the "Read Me" File for the Evasions download.

- Please disable the lock passcode of your iOS device before using evasi0n. It can cause issues.