First, the ShockLet. It somehow gets the data it needs:
the adress may be hardcoded or you allow the user to type it in like this one.
Don't expect miracles, the ShockLet won't explore the user's email adress unless you provide it.
Next, there is a cgi script. At the server, see for details on cgi.
This is in perl, it reads the input and prints it to the servers sendmail programm.
Last, the recipients email client. This bit is not provided.
You can download .dir and perl as a ZIP archive
and test, modify or use it as you like.
Please install your own cgi before you go live though.