In this thesis we place our research in the scope of a tool which looks for information within XML data on the Internet. We envision a personal schema querying system which enables a user to express his information need by specifying a personal XML schema. The user can also ask queries over his personal schema. The first task the personal schema querying system must perform is to match the personal schema against the real schemas of the XML data on the Internet. In this way, the system establishes a meaningful link between the user¿s information need and the data available on the Internet. The second task is the evaluation of the personal query, which is performed by means of distributed query processing.