To use functions provided by this module, the PHP binary must be built with the following configure line: --with-iconv[=DIR].
Note: Note to Windows® Users
In order to enable this module on a Windows® environment, you need to put a DLL file named iconv.dll or iconv-1.3.dll (prior to 4.2.1) which is bundled with the PHP/Win32 binary package into a directory specified by the PATH environment variable or one of the system directories of your Windows® installation. This module is part of PHP as of PHP 5 thus iconv.dll and php_iconv.dll is not needed anymore.