OverSite
If you design, develop, or architect Websites or other GUI-based software applications, then OverSite is the app you've been waiting for, even if you didn't know it. With OverSite, you can quickly define your site or application's structure. Creating wireframe mockups of your pages and screens is also a breeze. Once you're done, OverSite will auto-generate a structure map of your site or application, and will allow you to export to a number of different formats. Create wireframe and attach notes to them.
Version 2.4.6 has added the ability to change the name of a version and added the ability to reset the divider location to its default location.