...in PS CS5.
If you, like me, intensely dislike using the bracket keys for changing your brush size and then making still another movement to adjust the brush softness, then you are going to LOVE this new producticity tool that works with the brush-type tools:
Mac: ctrl+opt
Windows: alt+right-click
--drag to the left to decrease brush size, to the right to increase it
--drag down to make the brush harder, up to make it softer