PHP 5.1.3 was just released, including the latest PDO and PDO drivers. If you're still running older releases of PHP you should probably upgrade. If you don't want to upgrade the PHP core then you'll be pleased to know that I've also released the PHP 5.1.3 versions of PDO, PDO::MYSQL, PDO::PGSQL, PDO::SQLITE and PDO::ODBC to PECL--these are the versions that I've had time to personally test.
These are identical to the code in PHP 5.1.3, with the exception of PDO::ODBC, which includes two additional bug fixes that didn't make it in time.
On a related note, I noticed that people were downloading PHP 5.1.2 and then trying to build older PDO drivers from PECL into it, and then filing bugs when it didn't work. Don't do that; it really doesn't make sense. As a general rule, PHP 5.1 and higher bundle PDO, so if the version of PHP you are using is newer than the latest PECL package, stick with the version of PDO that ships with PHP. If the PECL package is newer, then go for that instead.