The one I have for Morgan is made by Outward Hound and is an ok pack. It comes as a combo pack pack/harness system. It was not that expensive and carries around all his stuff. If I was going to do a lot of hiking with him where he needed to carry more weight, I would get the palisades system that some others have on the board. It looks like a much more durable system however, the Outward Hound one that I have is good and is much cheaper.
Here he is the first time I put it on him
he seems to like it and had no problem getting used to it.