Thanks for the pointer, I'll have a look. But I must say that I'm a real fan of CMAP. IHMC has (I think) spent a lot of grant money and time developing CMAP, and it shows. For good or ill, I think CMAP is also used at DARPA, as I think it was their grant money.
At IHMC the software is developed by the same team that developed the associated learning theory. The result is that the tool is robust and the underlying paradigm is also sturdy. It was a couple of years ago, but at that time CMAP was miles ahead of MindMap, (though they address slightly different purposes).
I'm no expert on the state-of-the-art in knowledge capture tools, so the same capability may exist in these other tools that have been mentioned. And it may also be that these other tools better address child/youth learning. I can say that CMAP has been very helpful to me in capturing and articulating complex ideas to others (for example, in formulating a patent).
Long story short, I'm still interested to get CMAP on my EEE PC

Thanks and Regards,
Owen