I will get you something that may be of use to you. I use it with Teamspeak currently(it's what it was made for), but I'm sure with some tweaking if someone wanted to pick it apart you could apply it to whatever you want. I dont' have the link right now but as soon as if I get off work(aka 10 min) I will run home and find the link for ya.
almost forgot to tell you what the program does:
while teamspeak is running, this plugin program when used with winamp lowers the volume of whatever mp3 is playing so you can hear people talking, and when their not, the volume of the music goes back up. so when i play music at full blast, and someone says something it will just tone it down enough so i can hear them. It's also very adjustable settings as well. I think it was programmed in VB or something. not sure, but I'm sure once I link it someone can pick it apart.