>I've got a ton of reference material - you might want to start with Don Box's
Essential COM and
Effective COM: 50 Ways to Improve Your COM
and MTS-Based Applications.
Unless you're heavy into C++ these books are a bad choice to
learn about COM. They deal with issues at a much lower level
which is great for system integrators, but doesn't really help
much for developers using VB or VFP.
A great text on COM on that level is:
Distributed Applications with Visual Basic 6.0
by Ted Pattison
Microsoft Press
This book deals with the COM overview and the details of how
marshalling and threading works in addition to dealing with
MTS and Message Queue (although the latter is really lite).