Q: how can i cancel my cloud account?

If you no longer want to use iCloud, save any photo stream photos that you want to keep to your camera roll, then email any synced notes that you want to keep to yourself, then go to Settings>iCloud, tap Delete Account and provide the password when prompted (if running iOS 7).  When you delete the account you will be given the option to keep the rest of your iCloud data on your phone or delete it.