Left Downwind Abeam The Tower

On downwind abeam the tower I'm going 80 MPH on a heading of 030 at 6000 ft MSL. That is I'm parallel the runway I'm going to land on (21 Left), about a quarter mile away, and the tower is on my left. This is no time to mess around. There could very well be other airplanes in the pattern so we need to be pretty precise in our actions. In fact there are other planes in the pattern or the controller would have give me permission to land earlier. I'm number two and have not been given permission to land. I need to let the controller know that I'm looking for the other airplane and when I have him located to let him know.