I need to identify the best document transmittal systems for a real
estate development company.  The company has to track what documents
(architect blueprints, study reports, letters from government
agencies, etc.) it has received, and what documents it has sent, for
legal purposes so that if there is every any question, there is a
paper trail for documents both sent and received.  Also, the company
simply needs to keep track of all of its inbound and outbound
communications, and who has what information.

The term "document transmittal system" seems to refer to such a
tracking system.  It has to cover documents sent by mail, fax, and
possibly also by email, somehow.  One person told me that there is
such a system integrated with Microsoft Project or Microsoft Exchange
Server.  But, I may be overcomplicating what this is, as I only heard
of the term recently.  Does anyone know the leading document
transmittal systems for small businesses (e.g. less than 50 people,
less than 1000 documents/month)?

I assume that any system would have some kind of paper component, for
filing and tracking documents, perhaps stamping them?  Along with any
software component.

Help would be much appreciated.  If the answer could also provide some
context to explain how such a transmittal system works, that would be
helpful.  Also, the company does not have an IT budget so it is
looking for relatively simple plug and play stuff where it doesn't
take forever to figure out software.