I've built PHP 5.3.8 RPM packages with various common extensions (and the latest OCI8 1.4.6) for Linux x64. They are downloadable at oss.oracle.com/projects/php/. These binaries might be useful for quick testing. They are unsupported.
Oracle customers with support using Oracle Linux 5.6+ may prefer the stable PHP 5.3.3 php53-* packages available on ULN. The OCI8 extension is also available there.