If you have a Wifi-radio, you can stream music from Spotify (or iTunes) to the radio. That means you can have your Pc in your office or something and listen to your music were ever you have your radio. I have a Pinell radio in the kictchen.
How to do this:
First you must have a Pc with Windows, Spotify, wireless network, and a wifi-radio.
a) Close Spotify and/or iTunes. Make sure you exit the program.
b) Locate your program folder. This is usually C:/Program files/Spotify/ and C:/Program files/iTunes/
c) Download DSBridge from http://code.google.com/p/dsbridge/. You need the files "DSound.dll" and "dsbridge.ini". Put these in your Spotify and/or iTunes folder. (You might need to make admin privileges to do this if you use Windows 7)
d) Download Lame MP3 Encoder from http://www.free-codecs.com/Lame_Encoder_download.htm.Here you need the file "lame_enc.dll". Put this in your Spotify and/or iTunes folder.
e) Start Spotify or iTunes and play something. You will now se a new icon in your tray, a colored ball. This shows that your streamserver is active.
f) If you have an Internet Radio, go to your Internet radio portal page and find something like My added station, My favorites or something simular (See the instructions for your radio to find the adresses)
g) Find your computers IP adress by click on Start and then type 'CMD' in the search bar and press enter. In the new window, type in 'ipconfig' and press enter. Your IP will be something like 192.168.1.XXX.
h) At your Internet radio portal page, add a new station and call it Spotify or whatever you want. Type in your IP and the port for the streamserver. The port is 8124, so your IP shal look something like http://192.168.1.101:8124/ The format is MP3 if you have to set this. Save your settings
i) Make sure your WIFI radio is at the same network as your Pc. Find your new added station on your radio and you are ready to go! I have to make sure the music is playing before entering the radio, but this might not be a problem for yoy.
If you have a wifi-radio without internetportal, you should have te opportunity to manual enter the IP for your streamserver direct in the radio menu.
EDIT: If you're having problem, it might be the firewall causing this. Either on your computer or in the router. See this for how to open ports and forward on routers: http://www.wikihow.com/Set-Up-Port-Forwarding-on-a-Router