brake problems

[derrickmd18 at juno.com (der flo)]

I have a scirocco 16v and when I press on the brakes the pedal goes down
and after a few seconds it goes down another inch or two.  it almost goes
to the floor.  it stops the car but it goes down and after a few seconds
down some more.  I bleed the brakes a little Tuesday and it was perfectly
fine until today when it started up again.  do u guys think about it?  I
don't know whats wrong with it.  I'm going to pressure bleed the brakes
tomorrow and if it doesn't fix it I'm going to get a master cylinder.