I recently downloaded the latest Openid library for PHP and got the follwoing deprecated errors when trying to run the example in my webbrowser:

Deprecated: Assigning the return value of new by reference is deprecated in /php-openid-1.2.3/Auth/OpenID/Consumer.php on line 266

Deprecated: Assigning the return value of new by reference is deprecated in /php-openid-1.2.3/Auth/OpenID/Consumer.php on line 298

It seems to be only an issue with PHP 5.3 and I found a great fix at Miguel Santirso Blog.
He has gone through quite some trouble to fix all the compatibility issues with PHP 5.3 and and was so kind to provide his fixed version for download.