OpenSuse 11.3 allows you to control the volume of individual applications just like Windows 7. To use this you must download the Veromix applet.
To install, first make sure the following apps are installed in yast:
Now right click on the task bar, then "Add widgets", then "Get new widgets" button.
Then type Veromix in the search and click on the install button.
Now you can add it to the task bar.