PHP was earlier released under both GPL (General Public License) and its own license, which left the individual user free to choose the license they preferred. Now the program as a whole is released under its own extremely laissez-faire PHP4 license (http://download.php.net/license/2_02.txt).
At the time of writing, the Zend license was released under the QPL (Q Public License). Please refer http://www.zend.com/license/ZendLicense/ for more details. Also quoted in their press release is the change to BSD-style license, to provide compatibility with the PHP license, and offer greater freedom of development.