ResEx: an editor for translating resource files
Jeremy found a good companion to Resource Refactoring tool to make working with localized resource files much easier. Once you created resource files using Resource Refactoring Tool, you can use ResEx to translate resource files in to different cultures. ResEx will automatically create the resource files for the new languages as you add entries. ResEx project seems to be at an early stage of development, but I had no problems with it when I tried it.
You can download ResEx at this link: http://www.papadi.gr/Default.aspx?TabId=290