Matthias Keifer's KBabel1 is a translation assistance tool for editing and managing GNU gettext PO files. The main PO file editor has the ability to search for translations in multiple dictionaries, includes spell and syntax checking, and has the ability to show diffs. The program also includes a catalog manager to help one keep track of PO files, a stand-alone dictionary application, and a “rough translation” tool which allows you to create a set of rough translations from dictionaries as a starting point.
1. KBabel, http://i18n.kde.org/tools/kbabel/.