I used to be able to use btnx in ubuntu 11.10 to do this, but now i can't find the software from the software centre. can anyone help me with this?
Did not work for me. Better follow these instructions: How to set volume control using a mouse shortcut?
if needed: sudo apt-get install indicator-applet-complete then: Ctrl-Windows-right_click on top panel -> Add to Panel... -> Indicator Applet Complete
If you want to change the volume with the wheel of the mouse when you are in the corners of the screen, I can suggest you this : Volumouse for Linux