http://www.crumhorn-labs.com/

We are very proud indeed to present Hauptwerk version 2, the pioneering virtual organ system that can bring the experience and sound of playing any pipe organ from anywhere in the world within the reach of almost anyone with a home computer and MIDI keyboard or MIDI sequencer, with incredible realism down to every last acoustic nuance and functional detail, whilst also powering the next generation of electronic digital organs and voice expanders for both classical organs and theatre organs.

The latest news: Hauptwerk is now available for the Apple Mac (Intel and G4/G5) as well as Windows PCs. It performs so well on the current Mac range and OS X that we now recommend them as an ideal platform for Hauptwerk.

Via: Opaco.org