I just submitted my iPhone application using iTunes Connect, but I don’t see anywhere that they ask what version I used to compile my app? The binary I submitted used the 3.0 SDK (I used the drop down menu on the top left corner of xcode), is that right?
How about the build settings? iPhone OS deployment Target and Base SDK? what value should I set there?
The OS version is embedded in the Info.plist file of your application, and is taken from the Deployment Target setting of your project target. That will be the minimum OS your app will require in order to run. The Base SDK must be greater than or equal to the Deployment Target setting.
Note too that even if you never call one of the new iPhone OS 3.0 APIs (so your app would run fine on a device running OS 2.2.1) but set the Deployment Target to 3.0, the minimum required OS would be 3.0.