CS Odessa has released a beta version of its mind mapping tool (http://www.conceptdraw.com/en/mindwave) for Google Wave. This is a no-charge add-in to Google Wave that can be used as part of Google Wave to map out a strategy or brainstorm on a critical topic.
The ConceptDraw MindWave for Google Wave tool allows teams to collaborate on a mind map in an interactive flowing manner building a map structure that represents the planned work. The map add-in supports Google Wave playback that allows one to step back through a map.
Once a mind map is has the contents from the interactive session the mind map file can then be downloaded to one’s desktop to be further developed using ConceptDraw MindMap for Ma OS X or Windows.
Just remember: beta software is unfinished software. So use with care.