There is such an event (MailItem.BeforeDelete), the problem is it is only
available in Outlook 2002 and up.
You can also use MAPIFolder.Items.ItemRemove event; unfortunately it does
not pass the item being deleted as the parameter, so you will need to rescan
the whole folder to figure out what was deleted.
Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool