A book "ASP.NET MVC 1.0 Test Driven Development" contains pictures like
and
Unfortunately Emad Ibrahim (the book's author) doesn't know what software was used, he told the publisher did it for him.
Maybe you know what it is. I believe it isn't Balsamiq Mockups.
Many thanks!
While I don't know what program the author used to create these specific mock-ups, but I know of two programs you can use to create similar prototypes and diagrams.
For diagrams, I've found that SimpleDiagrams is an excellent "virtual pen and paper" program for creating freestyle diagrams without getting in your way. It's also very cheap as far as prototyping tools go: $19 for a personal use license.
For prototyping, there are plenty of tools to choose from. Pencil (there is also a standalone version of the application) seems to be a fairly useful tool if you're only looking for a tool to do rough sketches of the UI when detailing the UI requirements. This tool and many others have been discussed in detail elsewhere already, and won't be re-hashed here.
Hope this helps!