I'm programming an app that will have a free version. I have added another target to my app (MyApp Free) and am wondering how I can now add the proper #ifdef declarations to my code. If anyone knows of a tutorial or can provide me with more information on this I will be very grateful.
Keith Peters has a great tutorial on this: http://www.bit-101.com/blog/?p=2098
As for me, I just released two apps, one a lite version of the other. I set up two different projects, with the lite version getting most of its code from the non-lite one. Personally, I like having it separate like this (though by no means am I saying it's the preferred/good-practice way of doing this).
In the future, for what it's worth, I plan on just having one version in the App Store and enabling the premium features with an In-App purchase. Unlocking functionality seems really easy to implement with In-App purchases...