(I submitted this a few days ago but I think I messed up the submission.)

This is a site I've been working on recently to help developers avoid the traps and pitfalls that are hiding behind every corner when trying to internationalise a software project:

http://i18n.tumblr.com

It's not specifically a technical resource; there are plenty of those out there... it's more designed to change the way developers think about languages and locales, and the interesting problems they create in software. Feedback! Comments!