Straightforward Steps to get PHP Yaz to work on win32:
Download latest verion of php_yaz.dll and copy to your PHP extensions directory
http://ftp.indexdata.dk/pub/phpyaz/
Download latest version of YAZ toolkit and install it
http://www.indexdata.dk/yaz/
Go to the YAZ toolkit directory
(Most likely C:\Program Files\YAZ\bin)
Copy the 4 DLL files in that folder into your win32 directory
Uncomment the "extention=php_yaz.dll;" line in php.ini
Restart your web server.
Uninstall the YAZ toolkit if you wish.