I have been looking for a simple remote solution for my Windows media center pc. My audio system is connected to it so i needed a way to stream audio wirelessly from iTunes. I have used the Airfoil for Windows free but it starts garbling sound after a while if you dont buy a copy. I am trying to keep my media center mostly using open source software. Two softwares have actually made this possible for me.
I can now stream both audio and video over Airplay from my iPhone or iTunes on my laptop and its FREE!!!!
For streaming audio over Airplay i use Shairport4w which is located at http://sourceforge.net/projects/shairport4w/
Sharepoint4w allows you to make any Windows machine into an iTunes speaker making it very easy to send music to it. It has settings to allow a user to set a password on it so not everyone can send audio to it. It also allows for audio output selection. This helps if your audio system is not your default audio device. PERFECT!
Video Streaming / Photo Streaming
Streaming photos / video over airplay from iPhone to TV is a very useful and very cool feature to have. I use Windows Media Center for my media needs and i found a plugin which is also open source. It is called Airplay for Windows Media Center. Follow the link: http://thomaspleasance.com/2011/05/23/airplay-for-windows-media-center-beta-1/
These are free tools. If you find them useful support these creators by donating help or $$.
If you have any questions about how to use these tools let me know below. I can explain to you how to install them or use them.