I just recently got my first app on the app store. It's called "Bubble Notes" and it's pretty straightforward: mind mapping presented with a force directed algorithm.
My aim was to create a more streamline/simplified app more suited to quickly mapping out ideas (Individual maps are referred to as "Notebooks" in the app), rather than documenting complex relationships or generating professional or "enterprise" quality mind-maps.
I had a lot of fun making it and would greatly appreciate any comments, critique, and advice.
On the app store: http://itunes.apple.com/us/app/bubble-notes/id443144461