W00T I am 4 years from the feature sending you this message to the past!:
Hmm?
IP ban is found in the administration part of the website management. To unban yourself you should try one of the following:
1. Ask for apologize
2. Get a on someone else's computer (usually works in some situations)
3. Get a new IP (cloaking)
Not recommended (not even I do this to unban myself):
4. Hack the website to get hold of administration part of the website management and unban yourself, note that this is illigal and is not recommended to be done by anyone.
Recommended: Ask for apologize, usually the most effective, although if you happen to end up IP banned again because you mess up really bad somehow by breaking the rules then your chances of getting unbanned again is even lower. Also other people who own the website can "out of mistake" ban you again meaning you could tell that person (if you get hold of his email) that you got unbanned because you said sorry

).
Hope it helps....