Pentaho Data Integration/Kettle is an open source ETL tool that has been used by the presenter for two years. It allows users to extract, transform and load data from various sources like databases, files and NoSQL into destinations like data warehouses. Some advantages of Kettle include its graphical user interface, large library of components, performance processing large datasets, and ability to leverage Java libraries. The presenter demonstrates syncing and processing data between different sources using Kettle.