CADE (free)Cade is a tool developed by a company that focuses primarily on CAD. CADE is a 2D vector editor for Windows that can handle the task of diagramming your network with ease. One feature I really like about this tool is the ability to notate IP address, serial number, and manufacturer for each piece of equipment. CADE has all the stencils you need for a complete network diagram. CADE is free to use.
See the blog post, "Diagram your network with these tools", for details on submitting your own network diagrams.
Selena has been at TechRepublic since 2002. She is currently a Senior Editor with a background in technical writing, editing, and research. She edits Data Center, Linux and Open Source, Apple in the Enterprise, The Enterprise Cloud, Web Designer, and IT Security blogs.