Grazie, ho seguito la procedura guidata:
To create a signed and aligned .apk in Eclipse:
Select the project in the Package Explorer and select File > Export.
Open the Android folder, select Export Android Application, and click Next.
The Export Android Application wizard now starts, which will guide you through the process of signing your application, including steps for selecting the private key with which to sign the .apk (or creating a new keystore and private key).
Complete the Export Wizard and your application will be compiled, signed, aligned, and ready for distribution.