According to the instructions found here, to make your app state which screen sizes you can support, you'll need to compile your app against Android 1.6.
Using the minSdkVersion and targetSdkVersion this should run also on Android 1.5:
<uses-sdk android:minSdkVersion="3"
android:targetSdkVersion="4"/>
However, when I try to launch my app from Eclipse to run in a emulated 1.5, I get the following error:
Failed to find an AVD compatible with target 'Android 1.6'.
Is this an error of the eclipse tools/emulator? Or how do I get it to also target 1.5 correctly while giving me the option to specify the supported screens?