PHP Tarbackup is a simple class that allows backing up an entire Web site. It automatically works around timeout limits by splitting the job into multiple requests, allows tarball archive creation and updates, and comes with the Veloce script, which is very useful to automatically unpack tar.gz archives remotely and skip long waiting times due to FTP uploads.
AnyXML is an XML read-only class that offers PHP 5 SimpleXML's capabilities on any host, even those with PHP 4 or lacking the expat extension. It will automatically and transparently fail back to the fastest available solution, always offering a consistent API. It is a nice solution to PHP and XML troubles.