Strange... I was about to post a topic on exactly the same thing!
I have 2 sound cards connected to my PC... or more accurately 1 onboard and 1 seperate sound blaster for that lovely surround(ish) sound. I have the 4.1 (boo... need more) speakers connected to the sound blaster, and headphones connected to the onboard card. I'm looking for something that will let me switch outputs using a global hotkey. Also, since the media keys on the keyboard only let me change the volume of 1 soundcard at a time (without going through the control panel) it would be useful to have something that gives me a bit more control over the 2nd card.
I don't have anything like enough programming knowledge to design my own plugin... unless there are any *free* tutors out there