staritems.py: A python script used to migrate starred and liked items to a new Google Reader account.
With the required migration of account data and Google Reader data; subscriptions could be exported and imported, but starred and liked items could not. However, they could be exported as JSON. This script reads the JSON data and adds stars and likes to the items again.
There is a very basic implementaion as a web app here: greader (use at own risk).