OmniStat is a tweak that is useful in multiple ways through the Notification Center. What is does is gives you information about your device that you might need sometimes like your IP address, available space, free memory, and even your UDID(with a copy button). You can also use some of the controls it offers like the Bluetooth, WIFI, Power, Reboot, and other toggles. Overall, for a free tweak it looks great and is pretty useful. You can find OmniStat in the Cydia Store under the Big Boss Beta repo below.
Big Boss iOS 5 Beta Repo: