You may want to follow these instructions if you want to customize your SpringBoard. For example, you can change the status bar message 'No Service' to a string of your choice.
You will need to have jailbroken your device and installed iFile from Cydia.
Launch iFile by tapping its icon on your SpringBoard.
Press the back button until you get to the root directory of your device, then select System from the list of folders.
Press to select the Library folder then tap to select the CoreServices folder.
Tap to choose the SpringBoard.app folder then press to select the English.lproj folder.
Press to select SpringBoard.strings then choose Text Viewer from the popup menu that appears.
Navigate to the string you would like to customize then click the Edit button at the top left of the screen.
Change the value of the string variable to your liking then click the Save button.
You can now reboot your device for the changes to take effect!