Poedit

If you usually work with .po files, poEdit, this tiny but useful application will be really good for you.

poEdit shows data in very compact way, so you'll notice at a glance the terms you will have to translate without having to search the whole document. That fact will make your translation task to be shorter, that's really important.

Entries are arranged in a list, so that you can easily navigate large catalogs and immediately get an idea about how big part of the catalog is already translated, what needs translating and which parts are only translated in a fuzzy way.