Viito is an open source sign language image dictionary application that I’ve been developing for Maemo5 and the Nokia N900 on my free time. The latest version has now been promoted to Maemo Extras, which means that it gets listed in the application manager by default, allowing users to install it without much extra effort.
Viito uses image data from Papunet that has over 1800 sign images all licensed under creative commons. The application actually ships with all of them, so that offline operation is possible.
The application including the image data screen scraping utility is licensed under GPLv3, and the code is available as a git repository.