Programmatically reading Emails from Exchange Sever 2003

Question

We receive vendor confirmation of file feeds that we send out. Some of our vendors will only send the confirmation through email. I am trying to find some sample VB code that I can use to try and use, that I can schedule to go out and query an inbox and see if there is an email from a certain account and I then return the message body. A lot of the articles that I have found discuss using Web DAV, but I am unfamiliar with it as well as trying to query Exchange Server. I have found documentation for the apis for the new versions of Exchange Server, but I am having a hard time finding it for Exchange 2003.