I am getting going with Vegas 7. I apply video effects to clips by clicking on the effects icon in the clip and choosing the effect. I dont understand how do to this with audio effects. There are no effects icons on the audio clips. I can apply effects to entire audio tracks but how do I apply an audio effect to just an individual audio clip?
Pointers much appreciated.

Just put that event on a separate track and apply the effect to that track. Alternately, you could use a "non-realtime" effect on just that event. You could also keyframe it so that the effect is only on during the time of that event.