The latest version of the PHP language (in the 5.2 series) has been released - PHP 5.2.11:

The PHP development team would like to announce the immediate availability of PHP 5.2.11. This release focuses on improving the stability of the PHP 5.2.x branch with over 75 bug fixes, some of which are security related. All users of PHP 5.2 are encouraged to upgrade to this release.

Security updates include changes in image handling, exif processing, and popen crash issues. You can find out more about all of the changes included in this release in the Changelog and get more details on the release from the release notes. Both the unix source and Windows binaries are available.