Microsoft Office Visio Standard 2010

From Microsoft:

When you need to show the world what you mean, try Office Visio Standard 2007. IT and business professionals worldwide choose Visio to visualize, analyze, and communicate complex information, systems, and processes. Using diagrams, they gain insight into complex information, and use that knowledge to make better decisions for their businesses. You can too. Show the world what you're thinking with diagrams that literally complete the picture.