In xCode I click "Product -> build for -> profiling".
Then I hold down the run button until the drop down menu appears and select profiling. xCode runs and says "Finished running - Profiling MyApp.app on iDeviceName". However, the app never runs...
How do I build for profiling and then run?
Use,
Product -> Profile
from the Xcode menu. This will start up Instruments, and you can run the app from there.
Run the app on your device. Open instruments and then pick your target. Xcode 4.3.2 has serious issues with the profiling. This is the only workaround I've found