Hans Lellelid introduces Phing, a build tool for PHP projects. Phing allows developers to automate tasks like configuring, packaging, deploying, testing, and more through XML build files and tasks. It is based on Apache Ant and provides capabilities like selecting files with patterns, transforming files, running PHPUnit tests, and packaging code. Phing aims to be a familiar PHP-based build tool that integrates well with PHP applications and development workflows.