Some useful resources for the task:
Follow these steps to build a universal application that will run on both iPad and iPhone:
- Set the Base SDK build setting (in the Architectures section) to iPhone SDK 3.2.
- Set the iPhone OS Deployment Target build setting to iPhone OS 3.1.3 or earlier.
- Set the Targeted Device Family build option to iPhone/iPad.
- Make sure that your Architectures build setting uses both armv6 and armv7
- Set the Active SDK to iPhone Device 3.2, select your Distribution configuration, build (select the Build button) your application, and submit it for App review.