How to determine packages added after installation?

[Tom Browder <tom.browder@gmail.com>]

Is there any way to get a list of the default packages used for an
initial installation from CD?  I looked at my 10.04.1 CD and could
find only a limited set of packages (*.deb) under ./pool, and that is
obviously not all that were installed.

My purpose is so that I can ensure a co-worker has the same package
setup as I so our environments are identical.  I know I can do this by
comparing his installed package list versus mine. but it would be
easier if I could just tell him what I added after a default
installation.  A "Date-installed:" record in the package list file
(/var/lib/dpkg/status) would be helpful for compiling such a list (and
maybe a "How-installed:" record).

Thanks,

-Tom

Thomas M. Browder, Jr.
Niceville, Florida
USA