Add new tab/menu in ACP

[gungrave41]

How do i hook a new tab or menu in ACP.. possiibly with a template based on ACP theme... I've made a custom plugin where the custom profile fields goes thru a lookup table first to check if data exists... Now i need a tab in ACP where I can insert data so I don't need to access phpmyadmin whenever i need new info... Can someone guide me... thanks!