You will need to restore your device using the computer with which you last synced it. This allows you to reset your passcode and resync the data from the device (or restore from a backup).
If you restore on a different computer that was never synced with the device, you will be able to unlock the device for use and remove the passcode, but your data will not be present.
You may have to force iPad/iPod into Recovery Mode
Diavonex, I do wish you would stop passing on your information as it does not work.... at least not with losing all your data.
I too updated my I-Pad to IOS7 after my son-in law entered a 0000 passcode for restrictions etc but today I am asked for a four digit passcode which I have never used before and the 0000 doesn't do anything. Update finished without asking for any passcode input.
After logging on to I-Tunes I'm told that I can't connect because a passcode is required for my (already identified) I-Pad)
Now I-Pad is disabled so I cannot access I-Pad and because of that, I cannot access I-Tunes.
Well aware that I can reboot while losing all of my data but I've never had I-Cloud so I lose everything (not a lot) from my I-Pad through Apple's incompetence.
Should Apple release a fix for this bug then being unable to access either my I-Pad or I-Tunes, I will be unable to download it....................