I think it really depends on how you define photography. In essense, much of what photoshop does for a digital photo is little more than what can be accomplished in a darkroom. Dodging, burning, cropping, etc. All that happens in a darkroom just as it can happen on my photoshop screen. True, you can go much beyond darkroom techniques with PS, though, so the line becomes pretty blurry and gray.
Personally I think manipulations that don't affect the actual content of the photo are still to be considered photography. For example, I take a photo of my wife, convert it to b&w, increase the contrast a bit, and apply a softening filter. All I've done is the exact same thing I could do in a darkroom to a traditional film print. Now if I take a photo of my buddy and digitally affix his head to my dog's body, just for kicks, I've gone beyond the realm of photography and into "digital art" if you will.
But that's just me, personally. Talk to 10 different people in the hobby / trade, and you'll come up with 10 different (and probably VERY different) answers.