Are you a Force.com developer who wants to build apps for a global audience or an administrator of a multi-national organization with lots of customizations? Do the sheer numbers of custom labels that you need to translate make using the Translation Workbench unattractive?
If so, check out Localizing with the Force.com IDE, a new guide released with Summer '09. It provides step-by-step instructions for how to translate large numbers of custom labels more efficiently than with the Translation Workbench. It's guaranteed to save you loads of time and provides a good introduction to the IDE for those who have never used it before.