Go to
http://www.jforum.net/user/login.page and see the source code. There, in the <form> tag, you'll find some input hiddens with the module and the action. The login template you can find at templates/default/forum_login.htm. Is from there that the call is made, when you click the submit button.
( btw, all the hard work is done using reflection.. see Command.java )
Rafael
[originally posted on jforum.net by Rafael Steil]