After some consideration, I don't want to open source the application - unless I was abandoning it, which I am not!
However, I hope to support a plugin architecture in future releases to allow Java code to be written and run when lifecycle events in the application occur (eg new word loaded).
Let me know if you're interested.
Going forward, after the iPhone version, would like to do an Android version. And a web application for students to find each other in a virtual community.