Here is a link to the pentaho infocenter that explains how to do content linking within a single enterprise dashboard.
http://infocenter.pentaho.com/help/i...o_content.html
This links the different panels within a single dashboard.
If you are interested in passing parameters between completely different reports or dashboards, you will need to somehow set session variables which can be used by dashboards or reports. One way to set parameters is to use startup actions:
http://wiki.pentaho.com/display/Serv...ol+Data+Access (old but good)