You’ve probably seen the kind of photos I’m talking about. When a child has been missing for a long time, law enforcement can now use software to generate an image of what the child might look like at the present, given an older picture to work from. So I was wondering, is that software publicly available? It might be fun to play around with… maybe see if I turned out as projected 
I’m curious about the software too, though for a different reason. It’d be a one time thing though, so my wild guess would be that the expense would be cost prohibitive.
I don’t know if this is the case for certain, as I do not do age-enhancement work, but I am an art director and professional illustrator, and it seems to me that age-enhanced photos are created by artists based on old photos, photos of family members, and guesswork. I highly doubt that there is any kind of software package available that accomplishes age-enhancement by simply applying some sort of filter.
So the roundabout answer is, yes, programs such as Corel Painter and Adobe Photoshop are commercially available, but they are simply painting and image-editing programs and not ‘age-enhancing’ programs.
Well, I actually (God forbid) did some Googling on the subject myself, and it looks like Cuckoorex is pretty much right. There is a computer-based aspect to it, in that the program generates a “rough cut” based on the original photo and family members, but then a real artist goes over it to turn it into a finished product. You can read a bit about it here:
http://www.crimelibrary.com/criminal_mind/forensics/art/6.html?sect=21
So much for that novelty program… 
Last month, I was in Las Vegas. My hotel (CircusCircus) had a few photobooths that offered “facemorphing” for 5 bucks. The booth took a digital picture of my face, and merged it with another face. That face could be my friends face, if he woudl go into the booth after me, or it could be a models face from the booth’s collection.
Anyway, the booths software then *analyzed * the two facial characteristics and *merged * them into a new face. In this case, the face of our “child”.
The booth then gave a printout of our two faces and our virtual child. The funny thing was, the picture of the virtual kid really looked subtly like both our faces. The face-morphing software these booths use, probably uses some of the same principles the age-enhancement software uses.
Great amusement, for only 5 bucks! 
If I had offered up my own face twice, and chosen a daughter, it would have been interesting to see if my “daughters” face would have looked like my own, as in my own pictures from my youth. That would have been sorta similar to the experiment described in the OP.