How do you turn off your screensaver on Mac OS X 10.2?

I’m downloading something from the Internet and everytime the screensaver comes on, the downloads stop. How do I keep the screensaver from coming on so I don’t have to sit at the computer and move the mouse all the time?
For How do you turn off your screensaver on Mac OS X 10.2? try this:

• I'm on a 10.3.9 but it should be the same
  
  System Prefrences -> Desktop & Screen Saver
  
  There's a little box in the bottom left hand corner that says: "Start Screen Saver:" and then options like: 3, 5, 15, 30, 1hr, 2hr & never.
  
  Drag the arrow thing to 'Never' Should work.