Band-in-a-Box for iPhone is a program that works as a client to your existing copy of Band-in-a-Box allowing you to play, generate and transfer your songs to/from your iPhone or iPad.
Important: You need to have the desktop version of Band-in-a-Box for Windows (2011 or higher) to be able to generate / edit songs directly from the iPhone/iPad. However you can download and play existing songs from any Windows or Mac computer.