The GnomeTV applet is divided into four parts the upper-left button is to open and close the television window, the upper-right button is to open and close the teletext window. In the lower-left corner there are two buttons for switching channels up and down, the actual channel number is displayed in the lower-right corner.
By right-clicking on the applet you can move or remove the applet as you can do it with the most applet. You can find the channels and the properties menus here.