You can remove any icons from the Mac OS X dock by simply dragging it off the dock. You can add a icon by dragging that file on to the dock.
Don’t feel like dragging the icon? Okay, Okay I have another method for you. Simply right click on the icon you wish you remove and go to “Options” and select “Remove from Dock” Ta-da! Gone! Unfortuantly, there is no right click option for adding an icon to the dock.
View the video below to see it in action: