I *AM* replacing my clutch. This is not a "hey, my clutch is doing this...should I replace it?" question. However...

I have noticed that lately, when I engage the clutch, it "bounces." Hard to explain, but the car pulsates when this happends. It only last for a few seconds, and it stops. It's not a HUGE problem, but annoying. What could this be and will it be fixed w/new clutch/flywheel? Should I replace the slave cylinder as well?

Big thanks.