Vincent Danen recommends a couple of free mind-mapping applications, including MindMode, which is specifically for the Mac and also includes a premium version.
There has been great emphasis on enhanced productivity in the last few years, for business and personal means. Methodologies like Getting Things Done (GTD) have become very popular and a number of programs like OmniFocus and Things have been written to enhance productivity and make implementing the idea of GTD easy.
Another creative productivity mechanism that is becoming increasingly popular is called Mind Mapping. A mind map is a way to diagram thoughts -- words, tasks, and ideas in a linear way. Each mind map has a central idea or concept and then other ideas branch out from there, with subsequent branches from those ideas. It is a way to articulate thoughts and organize them into categories and by importance in a visual way that a traditional hierarchal TODO list cannot. It is also a fantastic way to brainstorm ideas.
While mind mapping has often been done on paper, with colors and line styles and pictures, software is available that can help create mind maps. One such tool is FreeMind, a java application that will run on the Mac, Linux, or Windows. It is open source and freely available.
Another tool written specifically for the Mac is MindNode that comes in three versions: the free and Pro version for OS X, and MindNode (touch) that works on the iPhone, iPod Touch, and iPad. MindNode Pro is fairly inexpensive ($25USD) and adds a number of neat features over the free version, but the free version is no slouch. It also interoperates with FreeMind and can export to the FreeMind format, as well as to PDF, graphic files such as PNG, to HTML, and more. So whether you want to share your mind map or move to another application, MindNode doesn't keep you locked in.
MindNode Pro gives you more ways to tweak and view your mind map, such as folding nodes, embedded hyperlinks, node reorganization, embedding files and images, and a full screen mode. It also enables Wi-Fi sharing with the MindNode (touch) program.
Because mind mapping is relatively simplistic, MindNode is a simplistic tool that doesn't offer a lot to get in the way or make it complex to use. When you open it, you're presented with a blank canvas and the main node. From there, you simply click and drag the "+" icon to create a new child node. Nodes can be dragged to be reorganized, and new child or sibling nodes are created by clicking the "+" icon next to the node you want a child from.
Each new child node from the main node will have a different color, which is customizable and changeable via the inspector. Each child node of that child will have lines of decreasing thickness, and you can customize the style of line as well (dotted, dashed, straight). You can also have more than one main node, so you can have multiple mind maps that may be somewhat related on the same canvas.
Screenshot courtesy of http://www.mindnode.com. Click to enlarge.
Mind mapping is a refreshingly different way to lay out ideas in a way that is easy to read and follow. It can make brainstorming easy, by logically following one idea to another, and can be used for any number of uses: planning a vacation, software development, charting personal or corporate goals, creating visual TODO lists, and more. MindNode itself is worth checking out, and if you want the added features that MindNode Pro provides, the cost is really quite reasonable. If you want to be able to use the same program on multiple platforms, FreeMind is a good choice as well.