SmartDraw packages a broad pallet of diagram templates that can be used to visually present everything from physical network layouts to database designs to mind maps and furniture positioning ...

Lovely Charts is a free web-based tool for creating flow charts, site maps, network diagrams, and other visualizations with a drag-and-drop interface and a look somewhat upscale from black-line boxes ...

Does anyone know what application MS used to create the network diagrams in the resource kit books? I remember reading about it somewhere but my memory fails me right now.