It is not recommended to install PHP 4.  Use PHP 5.2 instead. There was extensive re-factoring of the oci8 extension done in PHP 5.1.2.  These changes stabilize and optimize the extension. Note the options to "configure" changed slightly - see my installation guide.

There is a lot of information on Oracle and PHP available on http://www.oracle.com/technology/tech/php/index.html including a note (written by me) on installing PHP with Oracle Instant Client: http://www.oracle.com/technology/pub/notes/technote_php_instant.html

For readers stuck with PHP 4, you can use the latest version of the extension by downloading it from http://pecl.php.net/package/oci8 or http://pecl4win.php.net/ext.php/php_oci8.dll

 -- cj