At the moment I have two versions of my App: normal and plus
When I puplish a new relese I export it and then change the packet name and export it a second time. The plus version has some additional features which get unlocked by the package name..
I just discovered Android Library Projects (http://bit.ly/voHVWe) and now I wonder if that could be solution for optimizing the workflow decribed above? A further question is, are there any more (dis-)advantages of using library projects? - or would you propose another workflow?
Library projects can help you do exactly what you're looking to do. They're essentially like having an external assembly. All shared code would be in the library project, and each application (in your case, normal and plus) could utilize or inherit from the shared library code.
One gotcha for the library projects is that you need to make sure the application projects are using the latest version of the library project if you make any changes to it. I've been bitten before when I made a change to a lib project, and built the application to find out that it was using the old code (in eclipse just select the greyed out project, right-click and refresh).