The autocomplete e-mail cache used by Outlook 2002/2003 is stored in a file with the extension *.nk2. Microsoft hasn't released an editor for the cache file, but a 3rd party cache viewer called Ingressor (formerly OWTLOOK) is available from http://www.ingressor.com/ingressor_products.htm .

While the vast majority of users will have no need to view or edit the cache, since removing old addresses requires just the Del key (after selecting the entry using the arrow keys), some sites may have good business reasons for viewing or exporting the addresses contained in the cache file.