I want to change the name which is displayed below the app icon on the iPhone screen. I use Xcode 4 and I have one target with keys:
In recent versions of XCode (I am on 4.3.2 currently), $(PRODUCT_NAME) is set to $(TARGET_NAME) which defaults to the name of the project directory (no don't change the directory name).
Solution: Click on the file navigator. Click on your blue project icon. Look for the TARGETS list (under the PROJECT list). Hover-click your target; then rename it to your product name.
Aside: If you are having code-signing problems, I found that deleting, revoking, and regenerating all certificates/keys, and profiles fixed my problem. I tried everything else first!