These are extremely high level Arch Diagrams IMO. You could use Visio , SmartDraw, Visual Paradigm or any UML friendly tool you are comfortable with. I think all these and more tools out there will provide you with the functionality you are looking at.
On MacOS X, you can use OmniGraffle. It's like Visio, but with a Mac flair.
I second the recommendation of OmniGraffle, there are variety of free stencils available from graffletopia. Allowing you to do everything from UML to GUI layouts
It's not strictly a diagramming tool, but Inkscape is an excellent open source vector package that I've found useful for both general graphics but also diagrams.
I used SmartDraw in college as that was what the school provided and taught with, so I am a little biased towards it. There are also a number of free online solutions like this one:
There are others, I just don't happen to have the links handy at the moment.
Technically, any of a number of program you are familiar with will work just fine. You can even use your favorite office suite to do the same. due to various circumstances I've use MS Office and OpenOffice to generate charts in a pinch.