It supports all Google Translate languages, bi-directional translations, clipboard operations and allows you to send the translated text as an e-mail.
Screenshots (main screen and menu):


There is a bugtracker, if you find any bugs:
https://bugs.maemo.org/enter_bug.cgi?product=qTranslate
The .deb file is here:
http://maemo.org/packages/view/qtranslate/
And Mark Guim has posted a nice tutorial how to install .deb files on your N900, if you don't want to activate extras-devel:
http://thenokiablog.com/2010/01/28/how-to-install-deb-files-nokia-n900-x-terminal/