While I was working on the last update, editing the info.plist file to let the application use the black status bar, I noticed this strange option in the predefined values:
“Appliction is background only“. Application is also spelled wrong, maybe because it was a test feature that was not removed from the final build. Starting the program with this option doesn’t change nothing, and it runs as usually. The key in the xml file is named LSBackgroundOnly, and is the same key used to build background applications in MacOs.
Maybe this option was always here, and it was always useless. Maybe was just added for the 3.0 iPhone SDK just now. Maybe it’s an error. Maybe no. Who knows?
My personal opinion is that in future versions of the iPhone OS, Apple will permit developer to build background application, but the approval process will be restrictive and with lot of constraint (for example, to save battery life).
If you don’t trust the image, download the iphone sdk, create an empty project and edit the info.plist file.