With version 4.0 Microsoft CRM the option to have multiple languages in a single interface became available. To translate the various available labels CRM offers an option to export all labels to an excel file.
The problem I found with this file is that it lacks context of the text you are translating. For instance the text "Address 1: Line 1" this appears for each entity, form and view that uses this fields. So if you want to change only one label it will take you a lot of trial and error to find out which field you want to change.
For details how to added these columns to the excel file goto this page