Five-Column SpringBoard is a MobileSubstrate extension that adds a fifth column to your iPhone's home screen.
FCSB now works with firmwares 3.1+. 2.2 support has been removed for easier maintenance. 4x4 layouts persist after disabling FCSB.
A "pro" version of Five-Column SpringBoard called Iconoclasm that will be available on the Cydia Store by the end of the summer. It will allow anyone to create their own icon layouts an apply them through the Settings app. More details will be unveiled shortly.
Where did FCSB Toggle go?
FCSB Toggle used to be a standalone application; it is now available in the Settings application.