Using mouse scroll to change sound volume

It happens all the time that you need to change sound volume very quickly. You should know by now where the sound volume applet is located on the panel.
move you mouse pointer on it, and use the scroll button on the mouse to turn up or down the sound volume. No clicking is required.

Where is compiz manager?

You have installed Ubuntu 7.04 and you have activated "desktop effects" and now you have drop shadows under windows and menus and a rotating desktop cube. After a couple of hours you will start looking for somewhere to fine tune compiz. Compiz is what makes all these desktop effects possible.
In fact, there is a compiz manager. It is just not installed but no worries. Start synaptic, find and install:

gnome-compiz-manager

Now in terminal type:

gnome-compiz-preferences

and the setting manager for compiz fires up.
But you don't need to type this command every time. There is tiny application that reside in the panel and from where you can fire compiz manager in no time.
This application is called: compiz-tray-icon.
It is better to have it among startup applications so whenever Ubuntu starts up this application will be up and running. To do this, go to control centre, click on sessions and add

compiz-tray-icon

to "startup programs" tab.