Patch Route is a utility to create diagrams. It was originally created for studio musicians to detail the connections between pieces of equipment. It has since had networking equipment added for when you need to create a quick network diagram.
Pieces of equipment on the screen can be connected and the links will following movement of items. Text can be added to diagrams and dragged around as well.
The equipment database can be customized to create items with whatever name you wish to give them.
Export of diagrams via email (PNG image) is supported as well.
If you'd like more icons, email email@example.com and I'll see what I can do.
Black icon design by Sun Kissed Designs, http://sunkisseddesigns.com
Some icons used under Creative Commons License from Open Security Architecture.
Give those guys a visit, they're doing good things.