Do you mean the phone itself is disabled : If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support ?
Or your iTunes account : What to do after you change your Apple ID or password - Apple Support ? If that doesn't fix you account (if that is the problem) : http://www.apple.com/support/itunes/ww or https://www.apple.com/emea/support/itunes/contact.html