http://smedley.info/os2ports.html
he also has a build (1/20/2006) of version 5.1.2. It now includes a module for Apache 2.2, as well as CGI and CLI versions.
Also available (12/18/2004) is another port of PHP 4.3.10, which supports CURL 7.10.1, libxml2 2.5.8, libxslt 1.0.31, GDBM 1.7.3, MySQL client 3.23.49, PostgreSQL v7.2.2, ZLib v1.1.4, GD v2.0, FreeType v2.1.1, PDFLib v4.0.1, OpenSSL 0.9.7e, and Expat 1.95.6.
http://silk.apana.org.au/php/
For more info on PHP, see the PHP web site.
http://www.php.net/
Source: OS/2 Warp News and Rumors