.net smtp listener

Is there a way for using .net to create a console app. or service to listen for SMTP messages over a certain port?

I need to create a middle tier object that will capture and process smtp messages. That is to say i want smtp messages sent and picked up by this listener and then broken down to its basic components and persisted to a sql server DB.

If there is a off the shelf solution even better. I was not able to find one as I scurried the web.

Note: smtp sender will be a web app on the network, as well as exchange. The listener will be assigned some port so all smpt traffic on this port will be designated for my particular application.