hi guys i downloaded a plugin for visio called LANsurveyor Express which maps the networks automatically and no need of manual work. Its a product from solarwinds sponsored by microsoft. Last date for registration to get this free plugin is April 30th, 2009.
More Details about the tool and downloading instuctions is here (http://ebooksick.tradepub.com/free/w_msf73/?p=w_msf73)....
USA only!