Recently Microsoft published the Visio shapes for SharePoint 2010 to create create models of server deployment environments.
Upload them to the My Documents –> My Shapes folder to use them in Visio
Download:
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=88e03d22-8f42-4c9d-94ef-d8e48322d677
Rik Dekker 