Uh, Photoshop IS a program
Do you mean what photo editing program is best?
Probably Photoshop
You could also use the Gimp (its free)
Woof, Woof - Dawg
Erm.... Okay, I'll shoot. The best photoshop program is Photoshop. So go get CS 3.3....
But what is the newest version of photoshop then?