WTides is a free program that uses harmonics data to predict tide heights at many locations throughout the World, and displays a graph of the results according to the time zone of the target location.  The tide graph can be overlaid with a solunar chart to give an interesting version of the Maori Fishing Calendar.  The program runs on any version of Microsoft Windows from Windows 95.  You may freely download the software from here.
WTides is an enhanced port to Windows of David Flater's Unix program XTide. For information about the original program, click here.
There is no charge for the source code except for actual distribution costs, and no mandatory charge for the ready-to-use program, but contributions to expenses are readily accepted.