American Institute of Organbuilders (AIO) www.pipeorgan.org/
The Associated Pipe Organ Builders of America (APOBA) http://www.apoba.com/
Duane McGuire, Piano tuner/technician www.mcguirepiano.com/. Duane is a former employee whose ongoing interest, talent (in many areas), and friendship is always appreciated here.
Bring back the organ! - a compelling essay in favor of the pipe organ as the ideal musical instrument for the Christian church.
Just for fun:
Jesu, Joy of Man's Desiring on a gravity powered xylophone (on YouTube)
And for our theater organ friends (especially young ones):