Premier pro help

Click on the clip and go to the effects properties window and expand the volume properties.  Click the thing that turns key frames on.  Click the add a key frame button where you want it to start fading out and then click on the part that you want it to be completely faded out and drag the volume dial to -infinity or whatever it says.  It should add another keyframe and the fade should be made.  I haven't used premier in a while though.  It's something like that.

^you can do it that way... or just

go to transistions > auido tranisitions > power gain or whatever its called and drag it onto the end of the audio clip that you want to make fade out.

ya thats how you do