Where can you get the tm36 that contains sludge bomb on Pokemon XD gale of darkness?

In Pokémon XD: Gale of Darkness, you can obtain TM36, which contains Sludge Bomb, from the PokéSpot in the area of the game called Citadark Isle. After defeating the Cipher Peons and progressing through the story, you will find it in a chest in the area. Be sure to explore thoroughly, as some items can be easy to miss!