eDraw Mind Mapping is a vector-based mind mapping software with templates for brain-storming, project timelines, life planning, SWOT analysis and Sketch Maps. Free mind map software (Freeware,requires download)
MindMeister - a way you and your class can collaborate and create mind maps electronically! I always hated making mind maps because they seemed too messy and I could never seem to space and organize them correctly. This solves all those issues, and has perks like collaboration too!
Freemind: another open source (so free) gem. Once you learn to make notes in a mind map format you can never go back to plain text. It adds an extra dimension to your note taking making them so much more powerful and useful.