AirPlay lets you stream music throughout your entire house — wirelessly. AirPlay wireless technology will be fully integrated into speaker docks, AV receivers, and stereo systems from companies such as Bowers & Wilkins and Denon.
SoundWire lets you send any music or audio ("what you hear now") from your Windows or Linux PC to your Android mobile devices. Use it as:
Acoustic Bridge gives you the power to redirect audio from one PC to the speakers of another PC. This enables you to send the sound from a PC with your music collection to any other PC on your network. You could even visit friends and redirect your PC audio output to their PC...
This is a Java application to use the speaker connected to other computer on the network. It transfers audio in uncompressed PCM format and uses 172 kilobyte per second bandwidth.Discontinued
The official website is no longer available. Last version, 1.0, released in January 2014, can be still downloaded from Softpedia.
Share Speaker Player is an outstanding yet easy-to-use application to share speaker in LAN with high quality. It is a good way to decrease the cost of speaker in office, family, or other places especially with the world economy declining recently.Discontinued
The official website is no longer available. Last version, 1.10, released in August 2009, can be still downloaded from Wayback Machine