Notificator is a new jailbreak tweak developed by Alex McNight that brings system event notifications to your iPhone, iPod touch, or iPad so you can be alerted every time an action or event occurs. These events include, but are not limited to, installing a new application, connecting or disconnecting from a wireless network, switching cellular networks, and battery level alerts.
The tweak has options that can be configured in the Settings app such as the ability to create new events, set custom sounds for each different type of notification, and more. Notificator is a commercial package that can be purchased from the BigBoss repository in Cydia for 99 cents. iOS 5 or later is required.