On WebReference.com there's a recent article looking at the PEAR internationalization (i18n) packages and how they can be used to internationalize your application.

For many of us, the realization of the extent of countries' interdependence was driven home by the recent global economic meltdown. So what does all this have to do with us Web developers? It's a resounding wake up call that we have to think of other nationalities when we develop our websites and applications. In most cases, developing a web app in English alienates much of the world's population and greatly reduces potential profits! With that in mind, this article is the kickoff for a series that discusses the ramifications of globalization on our websites and applications.

The look at some of the local identifiers (like LC_ALL, LC_TIME, LC_ADDRESS and LANG), how to access the values for them on the different OSes and how to use the I18N_Country and I18N_Language packages from the PEAR I18N package to handle some simple multi-language support.