+2  A: 
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateStyle:NSDateFormatterShortStyle];
NSString *dateFormat = [df dateFormat];
NSLog(@"Date format: %@", dateFormat);
[df release];

Just tested on OS X but this should also work in iOS.

Ole Begemann
Awesome, it does work. However if you use the combination date/time picker, the control knows to cut off the year (yyyy). How does it know to do this properly -- is the format stored somewhere else or does it perform internal parsing of the existing formats? For an example, use the US format to see the year cut off. Then switch the region to Bulgaria. The text is moved around, but the Bulgarian formats (NSDateFormatterShortStyle, LongStyle, etc) do not match it at all.
junkyspace
I asked the question here instead of as a comment: http://stackoverflow.com/questions/3858277/objective-c-iphone-how-does-the-date-time-picker-format-its-dates-e-g-strip
junkyspace