Damien Seguy wrote to let us know that Nexen.net has published their PHP statistics for May 2006 and PHP stats evolution for May 2006. He also provides a brief overview:

• PHP 4.4.2 will become the dominant version during June 2006.
• PHP 5.1.2 is now the dominant PHP 5 version.
• PHP 5 rises to 8%, and raises its adoption speed again.
• PHP 4.3.9 and older keep a marketshare of 46% this month.

Apparently those who predicted that most would upgrade straight to 5.1.x were right. :-)