По интересувах се за voice msg-ing м/у windoze и linux и м/у linux и linux и ето няколко полезни линка:
http://www.teamspeak.org/http://phpaint.sourceforge.net/pyvoicechat/ - A full-featured Yahoo client for LINUX with voice chat and webcam support. Mission: To focus on thorough Y! support on Linux only. Philosophy: Trying to do multi-protocol / cross-platform clients slows progress and results in half-baked support - One protocol, one OS...done well.
http://www.linuxmotors.com/phone/ - The phone program is an internet phone for linux . With linux, a full duplex sound board, speakers and a microphone, and a 24000 bits-per-second connection to the internet or better, you can talk with other people with the same setup over the internet.
http://speak-freely.sourceforge.net/ - Speak-Freely is an Internet voice application that allows you to talk (actually send voice, not typed characters) over the internet.
Speak-Freely is undergoing new development, ie. new documentation and support. We will try to limit the confusion.

'> Speak-Freely was written by John Walker (read more).
Speak-Freely requires that you meet the following conditions to communicate:
* A _true_ Internet IP address for either your computer or the person's computer you wish to talk to
* A way to share to one person or the other their real IP address, such as 63.157.141.2
* A microphone with working sound settings. (When is the last time you used or tested it?)
* A firewall that does not block the assigned UDP ports (2074 or 2075 typically)
* A Pentium II class computer for CELP and Speex compression, of at least 200-300Mhz.
* A dialup connection at least 28kb/sec. (most of you have faster computers and connections)
* Possibly a set of headphones instead of your speakers for at least one person communicating. Echo-cancellation is not programmed into the audio codecs.
http://www.hut.fi/u/rsaikkon/software/voicechat.html - (Unix, GPL) Voice chat via TCP/IP
Note: I (Riku Saikkonen, the author of voicechat) don't really maintain voicechat anymore, and no one else does either. If someone wants to start maintaining it, please contact me (my address is below).
Voicechat allows transferring bidirectional audio data in almost real time over a TCP/IP network such as the Internet. It is meant for two-person voice conversations, much like the telephone.
http://www.bahneman.com/liem/work/ztalk.html - Ztalk is a low-bandwidth, voice communication tool for tcp/ip networks. Its a fully functional, voice-messaging system that is perfect for low-bandwidth systems, such as SLIP, PPP or 56kbs links. Ztalk currently supports the SunOS, Linux, Irix and Freebsd operating systems. (A NeXT version is in the works as soon as it's converted to use the dsp audio).
*****Забележка - Не съм пробвал НИТО една от тези програми и не отговарям за нанесени щети върху вашия компютър. Инсталирайте на своя отговорност!!! Дано да съм бил полезен на някого. Peace!