The clicking noise came back in my right pedal.  It was nice and tight on the crank so I began to think it might be something inside.  So I went crazy and took it all apart.  Ball bearings, the works.  Shimano PD 324 Pedal Assembly.  Re-assembled and greased.  Now what I didn't know is that there is a lock nut that holds the cone nut in place and it's very difficult to hold the cone nut while tightening the lock nut.  I've seen a special tool that Shimano sells for this but it's more then the pedals themselves!!  The right pedal was fine but the left one kept tightening (cone nut kept tightening) while I rode.  I figure this is due to the rotation of the pedal on the left side being opposite of the right.  As I pedal the cone nut, not being locked down, is tightening against the bearings.  The right side only tightens against the lock nut.  So I rode down to my LBS, thinking they would have the tool, only to find out they claim there is no such tool and that you just need to jam a flat head screwdriver in there to hold the slightly larger cone nut while tightening the smaller lock nut with a socket.  Well, I had already tried that, but I don't have the nice vice to hold the pedal still in the process so I coughed up 20 bucks and had them do it.  I figure it's 20 bucks for a little more knowledge and I'm posting it here so I don't forget.