I'm a bit tired this evening, so I'll just post the links. Doom 2 windows port, Heavy Gear 2 and Quake 2 are the only games I'm aware use this.
http://web.archive.org/web/20030430080952/http://www.3dsoundsurge.com/features/articles/APIs/APIs-p5.html
http://www.ixbt.com/multimedia/ias_ear.html