I have pc without sound card (HP Proliant Microserver) and Iphone 4. They are connected by Wi-Fi. Can I stream audio from PC to Iphone somehow?
Because the PC isnt the one actualy playing the music, you should be able to do it without a soundcard.
I've used Air Playit myself, and it works flawlessly. With the right configuration, the devices dosent even need to be on the same network.
Air Playit - http://www.airplayit.com/streaming-music.htm