Apps that do not work on the iPhone 4
There seem to be some apps that will work on iOS4, but not the iPhone 4. Maybe because of the increased resolution, retina display...whatever.
CoPilot Live is definitely one. Comes up and works just fine on my iPhone 3GS with iOS4, but when I try to run it on the iPhone 4, it displays in one tiny corner of the screen. Weirder still, even though the display is miniature, the touch registers where the graphics should be if it were displaying properly.