I was releasing an app to the the Apple App store tonight (actually two apps, I've done an Atley Hunter ;-) )
One of my apps encountered a problem when I tried to upload my archive:
"This bundle is invalid. The UIDeviceFamily key must be present when requiring a MinimumOSVersion of at least 3.2."
This did confuse me for a while, I did a bit of research and this information is supposed to be set automatically with XCode when I set the target platform.
Given I was using Xamarin Studio I was a little unsure where I stood so i took a shot in the dark.
I changed the platform in Xamarin to Universal and then back to iPhone/iPod problem solved,
hope this tip helps someone