NTT DOCOMO announced today that it has developed a spatial audio transmission technology for mobile phones that enables a user to assign a spatial position to each sound source when listening to multiple sound sources, such as during a game or a conference call.

The new technology enables a user listening with headphones to hear each speaker's voice as if it were coming from a unique direction, creating a virtual face-to-face communication environment. 3D video games have offered this experience for a while and it works pretty well.
To have spatial sound sources on phone calls sounds interesting as long as you get good voice reception. These days I am still happy to hear one person loud a clearly.

While existing spatial audio transmission technologies independently process audio encoding/decoding and spatial audio synthesis, the new technology offers a more efficient method by integrating the two processes, thereby minimizing bitrate (or bandwidth) and computation loads suitable for mobile phones and other resource-limited devices.

DOCOMO will demonstrate its new spatial audio transmission technology using docomo PRO series HT-01A handsets during Wireless Technology Park 2009 at Pacifico Yokohama on May 12th and 13th.
Via this DoCoMo announcement.