Easy solution: (and NO you don’t need to to change the min-sdk value !!)
Step 1:
Change “project.properties” file
# Project target.
target=android-13
Step 2:
In Eclipse
Project > Clean... > (select your project) > Clean projects selected below > OK
For a complete explanation with real example use this tutorial http://www.monkeycoder.co.nz/Community/posts.php?topic=1121
Cheers !