The necessary software for translation is called "Qt Linguist 4". For Windows and MacOS X, it can be downloaded here: http://www.qt-apps.org/content/show.php/Qt+Linguist+Download?content=89360. Linux (and *BSD users) install it with the package manager of their distribution. Usually, installing the latest version of the Qt4 SDK together with Qt Creator will install the necessary files and "Qt Linguist 4" will show up in the program menu.