GroupMap is all about making team-based activities easier. You can create or select a map, then invite a team to comment, collaborate and even vote on the best ideas. Everyone gets to add their views to the brainstorming session and GroupMap collects these ideas and displays them all in a group view for comment and for voting. GroupMap is easy to use, offers a free account option, and gives every member of the team a voice when it comes to collaborating.
Link – http://www.groupmap.com/
These are just a few of the mind mapping tools available online. There are many other services available offering mind mapping resources and other useful brainstorming tools. It’s up to you to decide which is best to help you and your team organize your ideas.