You can download Pentaho Data Integration (PDI), also known as Kettle, from Sourceforge.net.
Go to http://www.pentaho.com/download/ if you are looking for Pentaho Enterprise Edition (EE) of PDI.
Kettle requires the Sun Java Runtime Environment (JRE) version 1.5 (also called 5.0 in some naming schemes) or newer. You can obtain a JRE for free from http://java.sun.com/.
PDI does not require installation. Simply unpack the zip file into a folder of your choice. On Unix-like operating systems, you will need to make the shell scripts executable by using the chmod command:
Kettle comes with a graphical user interface called Spoon and with scripts to execute transformations, Jobs and other tools. Continue the tutorial to know them.