I use spotify on windows and wanted to volume stop start, next track from my son's ipod, my ipad, the mobile phone (n78) or mylaptop.
So I wrote an application.
Here's how to test and make it work.
You can use your facebook login /email.
Start here
Step 1
Install the software to your windows machine running spotify.
http://hopgood.eu/connect/SpotifyController.msi
Step 2
Configure the controller / connector on your windows pc
Start, All Programs, Spotify Controller configure
change the line
user="mh"
to
user="youremailaddress"
then file save and file exit
Step 3
In your ipod / ipad / smartphone
http://hopgood.eu/connect/
Register your email address - enter your email address and click submit, then click play.
Step 4
Start the controller
Start, All Programs, Spotify Controller configure
Step 5
have fun!