Christopher Jones has noted that the latest version of the OCI8 drivers for PHP (in the PECL extension) have been pushed to the current stable package.

HP's OCI8 1.3.3 has support for Oracle's DRCP connection pooling and Fast Application Notification technologies giving it improved scalability and high availability. Overall, the re-architecture of the connection code is more stable. It fixes some obscure edge case issues and lets it handle re-started DB's better. Basic functionality is unchanged.

You can find out more about the package and download this latest edition from its PECL page or check out the whitepaper they recent;y wrote up about PHP and Oracle scalability.