Most of these actions were mentioned above.
I've collated them here.
Keyboard + Mouse (2 Buttons + Wheel) Combos
Copy Ctrl + drag (left mouse button)
Move Shift + drag (left mouse button)
Create Link/Shortcut Alt + drag (left mouse button)
Zoom (in & out) Ctrl + Scroll Wheel
Scroll (left & right) Alt + Scroll Wheel
OR
Shift + Scroll Wheel
This action depends on the program you are using (e.g. IIRC, Photoshop uses Alt and GIMP uses Shift).
Auto-Scroll (up & down, left & right) Scroll Wheel Button
Some programs allow auto-scrolling (e.g. Word, IE, Firefox).
This places a marker on the page.
The distance and location that you move the mouse pointer (relative to the marker) controls the speed and scroll direction.
You can also use drag (right mouse button), which will give you a menu of options (when you release it) including "Cancel".
This only applies to Windows (in Linux, the GUI uses the mouse differently).