how to implement usefully

Issue Summary

so i have this installed and it works well when i navigate to contact_anon/nid but how to i make this appear on a node? i am assuming i need to create a block that has some php to create a link to the current node (something like <?php
print $node->nid;
?>" rel="nofollow">Contact the author of this posting.), and then i can choose to show this block on only certain node types or nodes?, but what exactly is that process or code? i am trying to look up how the nid is passed to blocks but i am new. would this be best accomplished by integrating this module with the exiting anonymous contact or author contact modules which only work for logged in users?