go to the fossil maniacs house and talk to the little girl
you can get 28 dig on route 114
the TM dig is found in the Pokemon maniacs house on route 15
Dig is a TM, so you can teach it to it at any level.
That TM is given by a kid in the fossil maniac's house which is west from fallarbor town.
Other Pokemon do know dig without the TM dig. Most DIGlets know dig. Find diglets in Diglet cave. Hope this helps!
inside any cave or dungeon
the dig masters house in the town by all of the ashes. sorry name slipped my mind
Zigzagoon can be taught Dig at any level once you have TM 28. TM 28 can be found in Route 114.
first you have to pass the game, until then none
Nothing really, he just gives you a "Dig" TM.
Zigzagoon wouldn't be able to learn Dig by leveling up. You will need to give it the TM Dig to teach Zigzagoon.
you can't buy it,but you can get it in fallarbor town in one of the houses with tunnels