GTD-Free is an open-source project, you can use it for free and you can make improve the project for all in many ways. Here are some ideas.
You can contribute to the project by sharing your ideas in one of following discussion forums:
... or send e-mail directly to the author: ikesan_AT_users.sourceforge.net.
You can report bugs or submit feature request also to tracker tool:
Project is open for donations.
Translate GTD-Free into your favorite language. Simply download file below with messages and send back translated version.
At the moment there is one extension point in code. By implementing interface ExportAddOn.java developer can write owe export method and submit it to the project code base.
Proper plug-in framework is foreseen, but not with high priority.