HawkVoice is a game oriented, multiplayer voice over network API released under
the GNU Library General Public License (LGPL) , with support for Linux/UNIX 
systems and Windows 9x/ME/NT/2000/XP/CE. 

It is designed to be a portable, free, open source code alternative to the 
Microsoft DirectPlay Voice in DX8-9. It provides voice compression using several
free voice codecs. The very low bitrate (VLB) codecs, those less than 6 Kbps, 
are optimized for the compression of human speech.

WWW:	http://www.hawksoft.com/hawkvoice/