GTD-Free is an open-source project, you can use it for free and you can make improve the project in many way. 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.
Project is open for donations.
Translate GTD-Free into your favorite language. Simply download file with messages and send back translated.
GTD-Free source code is available here: