If you have recently upgraded your iPhone to OS 3.0.1 then you’ll need to run this command in terminal to allow you to continue to publish to your device via Xcode.
ln -s /Developer/Platforms/iPhoneOS.platform/DeviceSupport/3.0\ \(7A341\) /Developer/Platforms/iPhoneOS.platform/DeviceSupport/3.0.1
Without this change, you’ll get an error message and won’t be able to install your projects to your device.
