Many IS/IT departments are fully capable of developing Web sites, however, many prefer
to hire an outside firm for initial site development or site redesign.
The reasons are many: time/budget constraints, lack of artistic ability, benefits of having
an "outsider" view the site and process as if a potential customer, benefits of having an
"outsider" guide the process with competing departments and interests (e.g. my stuff is
more important than their stuff).
If you use an outside firm to develop your site, your IT staff should be an integral part of
the development process. Their suggestions and input may be critical and their
commitment to the project and ongoing maintenance are improved if they are
involved in the beginning and over the life of the project.