Poedit is cross-platform gettext catalogs (.po files) editor. It is built
with wxWindows toolkit and can run on any platform supported by it (although
it was tested only on Unix with GTK+ and Windows). It aims to provide more
convenient approach to editing catalogs than launching vi and editing the
file by hand. 

Here is a brief features list: 

   - User friendly way of editing entries. You can easily navigate in large
     catalogs, easily enter or modify entries (fuzzy flag is automatically
     removed if you change translation, you can copy original string to
     translation by pressing Alt-I) 
   - Whitespaces highlighting 
   - Fuzzy and untranslated records highlighting. Furthermore, untranslated
     and fuzzy translations are displayed at the top of the list 
   - Automatic compilation of .mo files (optional) 
   - Automatic headers update 
   - References browser lets you see where in what context the string is used 
   - You can use Poedit to scan source code for translatable strings 
   - Integration with KDE and GNOME desktops 

WWW: http://www.poedit.net/