PHPMaster.com has posted the second part of their series about localizing PHP applications "the right way" (hint: it uses gettext).

Welcome back to this series of articles which teach you how to localize your PHP applications using gettext and its PHP extension. In Part 1 you took your first steps towards towards this by installing gettext and Poedit, creating a translation file, and writing a Hello World script. In this part you’ll lean about each of the function used in the script, and dive more into the gettext library and its usage.

The explain some of the naming conventions gettext uses for things (like "domains" and "codeset") as well as the shorthand "_()" you can use to retrieve translated values. There's also a look at supporting multiple locales via multiple directories of .po and .mo files.