I'm still diging around the subject from my sloooooow link, and discovered quite a few interesting things on IBM web site (thanks to jweed) like iseries Perl of wisdom
Still remain some question, eg :

• is TN5250 scriptable like telnet {isn't it a telnet like } ?
• How does one install Perl on an AS400 ?
• Is DB2/400 connectivity identical to DB2/Unix or Win32 ?

.. still diging to try to complete the node, I will have access to a machine soon.