You can produce a decent tilt/shift effect in PP. My Tilt-Shift Instructions for GIMP : Bart Busschots
Let me echo Dao's comment -- Welcome Back!
Helen, great to see you again!!!!
Pete, regarding your comment on application in landscape work, I use slight tilt a great deal, predominantly with either a 65mm or 90mm(on 4x5) or a 120 (on 8x10), a slight tilt forward moves the focal plane closer to the ground (as you are aware, I'm sure), so when I emphasize the near/far juxatposition I am able to maintain focus on a plane reasonably coincident with the ground.
It's a technique that has been in use for over a decade, when done right, you don't notice it. When done wrong (excessive rear tilt causing geometric distortions, etc.) it's screams at you.
erie