Kim Black forwarded this excellent Blog on Mind Mapping with a Tablet PC.
Here is an excerpt from the article that I have editing slightly to bring this paragraph into context.
The main reason I mind map is because when you use a linear format rather than pieces radiating out from the center, the brain imposes a hierarchical structure on the content, regardless of whether one was intended. And this matters. It changes, even if subtly, the way you process and understand the material. Another thing mindmaps let you do is make connections between different nodes; something that’s especially hard (or impossible) to do with linear notes.
The complete Blog is here; Why I Want A Tablet PC