In gen 5 it's in the battle subway train station and in gen 4 the guy is in the battle towers or battle frontiers. Source http://bulbapedia.bulbagarden.net/wiki/Individual_values
That's how to figure out Ivs. To find out hidden power type go to veil stone city prize corner in diamond, pearl, and platinum. In hg ss it's in the celadon game corner. In black and white the hp teller is in the mistral ion city game corner.