Gtranslator is an enhanced gettext po file editor for the GNOME desktop environment. It handles all forms of gettext po files and includes very useful features like find/replace, translation memory, different translator profiles, messages table (for having an overview of the translations/messages in the po file), easy navigation and editing of translation messages and comments of the translation where accurate.
Gtranslator includes also a plugin system with many interesting plugins like alternate language, insert tags, integration with subversion and a source code viewer.