The CloverETL Community Edition is based on Open Source transformation engine and also includes a free Clover Designer.
Here is the link to CloverETL Community Edition.
More about CloverETL:
CloverETL is a Java based ETL tool with Open Source components. It can be used standalone – as a command-line application or server application or can be easily embedded in other application (as a Java library). CloverETL is accompanied by CloverGUI graphical user interface developed as Eclipse plugin. Data transformation is described by transformation graph that is represented by Java class. However, description of graphs can be stored also in XML format. Graph consists of nodes (perform various simple transformations) and edges (connect nodes and pass data around). Each node is run as separate thread which helps utilize more CPUs (cores). The Clover ETL engine can also be used in transaction mode – i.e. transformation graphs are executed repetitively as a step in transaction.
CloverETL can be easily extended by creating new custom components in Java. Such components can be registered within the GUI and used as any other component delivered in the standard pack.
Server version of CloverETL allows parallel execution of transformations and also supports execution of transformations in transaction mode. The server runs inside application container.