There are currently three software products available.
A Mail Manager for Microsoft Outlook (from 2000 onwards).
A freeware utility for downloading email from a POP server and forwarding to an SMTP server. Written to work primarily with Exchange in place of the SBS POP Connector (which is missing certain crucial features).
This is a COM library written in C++ that uses Extended MAPI to access various properties of Outlook objects without triggering the security prompt (which was introduced in Outlook 98 SP2).