User to send a list of selected nodes via e-mail to the admin I would like the users on a site to be able to select certain nodes and send a list of those nodes to one specific e-mail address.

Gathering the nodes is easy with Nodequeue or Flags, so is sending a mail with Action when a node is flagged. The problem is sending an email with the list when the user want to, when the list is final.

Do you know any solid solution for this problem?
If you don't have a custom module created yet, make one (always good to have at least one custom module for misc tasks).

Create a menu callback for sending the node information in you hook_menu().

function hook_menu(){
  return array(
    'user/%/sendNodes'=&gt;array(
      'type'=&gt;MENU_CALLBACK,
      'page callback' =&gt; 'hook_send_nodes',
      'page arguments' =&gt; array(1),
    ),
  );
}


Create the callback function to send the nodes.

function hook_send_nodes($uid){
  // Fetch all flagged nodes from database for this $uid.
  // Send this node information through drupal_mail(). 
  // After your nodes have been sent, use drupal_goto().     
}


So now, you can create a link to the URL user/UID/sendNodes and that will send the nodes.
Obviously this is all pseudo-code, but the idea is there.