“Since yesterday, KingsIsle has been mitigating severe DDOS attacks against our games Pirate101 and Wizard101,” KingsIsle reported. “This means your game play will be impacted until we can resolve the issue. Many will be unable to log in. We have always taken care of our community when trouble arrives, and we will be sure to do so again once the issue has been fully resolved.”
It looks as though some service has been restored to both games, although it doesn’t sound as if the attack is over.
Source: Official forums