I wanted the person receiving the 'Recommend to a Friend' email to have more info about the job. This explains how to add data to the email content.

Chrono gets the kudos for the 'how to'. I just typed it up for lesser coders. like me.

This example adds the Job Title and Company Name to the email as text (not links). To add other / more data just follow the same process with as many additions as you want.

1.    Open job-details.php and find the dynamic SMARTY code you want to add. For example:
{$job.company}
{$job.title}

2.    Open job.tpl and find the 'send-to-friend' form.
Add the SMARTY code you want to add as hidden fields just before SUBMIT. For example:
    <input type="hidden" name="employer_name" value="{$job.company}" />   
    <input type="hidden" name="job_title" value="{$job.title}" />
    <input type="submit" name="submit" id="submit" value="SUBMIT" />

3.    Open page_sendtofriend.php to include the new code.
    * NOTE: KEEP THE ORDER THE SAME AS THE HIDDEN FIELDS ORDER IN job.tpl. For example   
    if ($costel->MailSendToFriend($friend_email, $my_email, $my_message, $employer_name, $job_title))
   

4.    open class.Postman.php to add the code to the email itself. For example:
Add the string to the email content
        $msg .= "\n\n Company:  " . $employer_name. " \n Job Title: " . $job_title;