Windows
Installing PHP extensions on Windows is easy and the php_intl.dll extension should be bundled with the PHP installation (if it isn’t then it is likely the version of PHP you are installing is too low).
There are plenty of articles giving detailed steps for this if you search for php windows php_intl.dll, however the basic process is:
- Find the PHP installation, look in the ext folder and make sure the file php_intl.dll is present
- In the PHP installation, look for the php.ini file and open it with Notepad or similar text editor
- Search for php_intl.dll and you may find a commented out section. If you do then uncomment it (by removing the leading ; character). If you don’t then add a line for it:
extension=php_intl.dll
- Restart your Apache web server service
There are some more detailed instructions here which may be of use:
http://cynwong.com/blog/?p=442
Ubuntu / Debian
You’ll need to install the php5-intl
package