XMind – the basic version is free
XMind (shown in Figure 9-14) is an open-source package. This means that the source code can be viewed and further developed by anyone. The program is available in a reduced-function version free of charge and in a Pro-Version for payment.
Web-Based Mind-Mapping Programs
The list of web-based Mind-Mapping programs is more manageable than that for desktop versions, but the trend is definitely towards more and more online programs.