You can make a shortcut to your Sound Settings on your home page. Long press on your homepage and pick Shortcuts>App Actions>Settings>Sound Settings. That will give you one click access to change back and forth.
Or, as Greg Tal suggests, a widget will also do this. I like Widgetsoid which is a free app and will put various widgets either on your home screen or in your notification bar. It's a powerful app, which also means there's a number of options. So you would do well to look at the video on the Market and/or their Help page to learn how to fully exploit its options.