Make a backup first!
As the following steps involve corrupting Outlook's PST file, make a backup  
1.	To corrupt the PST file, open it with the hex editor of your choice. Ruckerconsulting.com/downloads
2.	Delete positions 7 through 13 with the spacebar. Since you're using hexadecimal numbering, this actually clears 13 characters in the following positions: 
3.	
00007
00008
00009
0000a
0000b
0000c
0000d
0000e
0000f
00010
00011
00012
00013
(The editor displays the code “20” each time you clear a position with the spacebar.) 
4.	After clearing those positions in the file, save it. Your PST is now corrupted. 
5.	Run the Inbox Repair Tool, SCANPST.exe, to recover the file. On Win2K and WinNT systems, the executable is located in C:\Program Files\Common Files\System\Mapi\1033\NT. You can also find it on the Office 2000 CD-ROM in Drive:\Pfiles\Common\System\Mapi\1033\NT. In WinXP, the file is located in C:\Program Files\Common Files\System\Mapi\1033. For additional information on the Inbox Repair Tool, see Microsoft Knowledge Base article 287497. 
6.	After creating a backup, the Inbox Repair Tool repairs the damage and recreates the PST. Open the new PST in Outlook. The Deleted Items folder should contain all removed messages, so anything you've emptied will be restored.