There are several PHP hosting companies that offer free PHP 5.2 engine already. However, it comes as a surprise to me that all of them refuse to offer PDO for MySQL or PosgreSQL. Instead, they offer PDO for Sqlite which can not be a serious option. I have tried 5 companies that offer free PHP 5.1+ hosting and see no difference.
For instance, you can have a look here: http://pcdinh.phpnet.us/info.php What happens to PDO? Have it been considered a dangerous extension or PHP 5.1+ new features are simply mysteries to hosting company's owners? Time of PHP 5.1+ seems to be a long way. Dinh