Here are the instructions on how to customize your iPhone carrier name and banner using FakeCarrier.
Press to launch Cydia from your Springboard and select the Sections tab from the bottom of the screen.
Press to select Utilities from the list of Sections.
Press to select FakeCarrier from the list of Packages.
Press the Install button at the top right of the screen and tap the Confirm button at the top right of the screen to begin installation
Once the application has installed successfully press the large Return to Cydia button.
Press the Home button to return to your Springboard then press to launch FakeCarrier.
Press the Fake Carrier button to customize your carrier name.
You can add your own carrier name then press the Set button to make it active. To return to the default carrier name press the Reset button.
To replace the time banner at the top of the screen press the Fake Time button from the main menu.
Input your own text for the banner then press the Set button to make it active. To return to the default time banner press the Reset button.