This article titled "i18n with PHP5: Pitfalls" discusses the caveats of doing internationalization with PHP in general and
PHP5 in particular. PHP5 inherited the PHP4's localization support that is far from being
perfect. The
problems start with the setLocale() function which is not cross-paltform. The article gives some tips on making a platform-independent setLocale() equivalent, as well as examines problems with strings collation, date and time
formatting, number formatting, multibyte strings and regular expressions. Where possible, workarounds are suggested for making i18n less painful.This article is a good read for beginners as well as advanced programmers as it pinpoints not so obvious problems. The article can be read here: http://www.onphp5.com/article/22