This article from TechRepublic.com discusses a rather unorthodox method for recovering deleted Outlook e-mail.  It has been discovered that by corrupting the .PST file in a very specific way, more often than not, deleted e-mail can be recovered.  The article assumes certain technical knowledge/understanding and it would be a good idea to back up your .PST file before attempting to perform the steps. 

dixlinx: ARTICLES.TECHREPUBLIC.COM

Tags: e-mail recovery, outlook mail recovery, recover deleted e-mail