I've had my puppy (almost 9 weeks old) for about 3 weeks now. I've been letting him "go" right outside of our back door (and into the backyard) because it's winter where I live and making a path through the snow would have been too hard since he was so little.
Well, I really don't want him going there once the warm weather returns and would rather he go on the far side of the yard. He's starting to be able to get around the snow now and has been expanding his um, poop circumference,

and though I'm glad he's at least going outside I really don't want his poop all over the yard.
Should I start training him now to go in the area I want him to and how do I go about that? Will a dog even want to go in the same area time and time again? If I waited until spring to train him would it be more difficult or is this something an older dog would pick up without any problems?
Thanks!