Can audio be streamd via WiFi?

Technically speaking, there's nothing special about an audio stream vs. regular data. The Wi-Fi radio just sees data and sends it.  Therefore, it really depends on the audio stream's bandwidth/throughput requirements.  QOS (packet prioritization) can be important for low latency audio/video streams. Depending on compression, buffering, and other A/V settings audio can technically be streamed via 802.11b. E.g. 720p video can be done via 802.11g.