It seems like the Flash Builder Burrito license/trial period has expired, so in order to develop AIR for Android apps, you’ll need to download/buy Flash Builder 4.5. Of course all you need to develop AIR4Android apps is the free Flex 4.5 SDK but it is infinitely easier with the IDE. Also, if you’re a student, you can get a free copy of the Flash Builder. Check this link.
Once you have Flash Builder 4.5 ready, go to File->New->Flex Mobile Project to create a new project. Follow the following instructions as shown in the screenshots. (Explanations coming soon)
Apps will be filtered in the Android market based on the permissions you set, so make sure to set them right.
Make sure that the Application ID is a unique key as the Android market uses this to identify your app.
Select the phone/device of your choice where you’d like to emulate the app.
Clicking the button will launch this website in a browser window from the AIR4Android app.
You can download the source of this Hello World project here.