I've started work on a free mind-mapping module for the NetBeans Platform (with graph.netbeans.org). Not planning anything fancy, just a well done NetBeans Platform-based application with help, autoupdate, etc.
I expect the feature list to be close to the features of FreeMind or other open-source tools.
What I do want is import from these other free formats in order to have a simple migration guide for the existing users.
I also planned some tutorials / podcasts as I come along but I think I'm overly optimist so I'll be happy if I just manage to finish the first version untill me self-declared deadline of 4th September 2006.