You may have heard of the Zend Core for Oracle; as part of that project the oci8 extension for PHP received a lot of attention from teams of people from Zend, Oracle and OmniTI. As a result, the oci8 extension is now more robust, performant, better documented and more thoroughly tested than ever before (the list of closed bugs is enourmous).
Although the extension is currently marked as beta, it's a significant improvement over the older versions that have shipped with PHP.
The updated code is available now via PECL, and will compile against PHP 4 and PHP 5 (Windows users can obtain the updated extension DLL via snaps).
Installation on unix should be as simple as:
# pear install oci8-beta
However, if you compiled the oci8 extension statically, you will need to recompile PHP using --with-oci8=shared (or --without-oci8) before this will work.
Updated documentation will be appearing at your local PHP documentation mirror as soon as the manual build finishes.
Many thanks to Antony Dovgal for doing the lions share of the implementation and testing; good work Tony!