Volume Scroller allows you to quickly change the system volume. All you have to do is hold the mouse pointer over the taskbar and turn the mouse wheel.
Scroll the Volume AlternativesVolume Control Tools and other similar apps like Scroll the Volume
Scroll the Volume is described as 'Instantly adjust your Mac’s volume with a smooth scroll gesture! Elegant, intuitive, and distraction-free—take full control of audio with just your fingertips' and is a Volume Control tool in the audio & music category. There are three alternatives to Scroll the Volume for Mac, Windows and Linux. The best Scroll the Volume alternative is Volume Scroller, which is both free and Open Source. Other great apps like Scroll the Volume are Volwheel and Volume Scroll.
Alternatives list
VolWheel is a little application which lets you control the sound volume easily through a tray icon you can scroll on. It is written in Perl/Gtk2 and works both for ALSA and OSS. You can configure it quickly through its configuration interface.
Volume Scroll lets you control your main volume by hovering with your mouse cursor over the top menubar and scrolling up or down to change your volume.
