Download:
http://www.ioncube.com/loaders.php
Installation on a Windows Server
You need a Loader called
ioncube_loader_win_<php flavour>.dll
<php flavour> will be 4.1, 4.2 or 4.3 - i.e the first 2 digits of your PHP version.
Edit your php.ini file and add:
zend_extension_ts = "<drive>:\<path>\ioncube_loader_win_<php flavour>.dll"
where <drive> and <path> locate the Loader, and <php flavour> is whatever the correct value is for your system. If there are other zend_extension entries in the php.ini file place this new entry before the existing entries.
e.g.
zend_extension_ts = c:\WINNT\ioncube_loader_win_4.3.dll