McMyAdmin
McMyAdmin is a web interface and administration utility for Minecraft Survival Multiplayer (SMP) servers. It lets you monitor the servers status, chat with users, manage groups and permissions, schedule events, perform updates and more.
Development on McMyAdmin started in October 2010, and it is now the most widely used Minecraft control panel in existance with over 10000 simultanious live servers. It is being offered by more than 20 different game server providers who rely on it to provide their end customers with an easy way to manage their servers without editing configuration files with more providers being added all the time.