debug iphone app wait for lunch

For Xcode 4 you have to:

1. Edit your active scheme via "Schemes" dropdown.
2. Than choose your product - 'Run MyApp.app' on the left.
3. Select 'Info' tab on the right.
4. And finally choose "Wait for MyApp.app to launch" option.

More here in "Customize Executables in the Scheme Editor" section.