Transifex-mobile first public release is available for download! Enable maemo-extras repository on your N900 and install package transifex-mobile. Icon should pop up in the menu afterwards. Current version supports logging in to Transifex.net, pulling PO-files, editing them and pushing them back to server.
I am very much interested in your feedback, dear translator! The package installs files under /opt/transifex-mobile and if for some reason the app doesn’t want to start, fire up terminal and run /opt/transifex-mobile/main.py.
You can track my GSoC 2010 project status on a wiki page with more detailed information here. Screencast will follow up in a day or so. Stay tuned!