Raikou and Entei
Raikou in our Pokedex: http://pokemon.supercheats.com/raikou/
Entei in our Pokedex: http://pokemon.supercheats.com/entei/
REQUIREMENTS: Release them from the Ecruteak Burnt Tower.
ABILITIES NEEDED: NONE
LEVEL: 40 Each
Once you release the 3 Legendary Dogs from the Burnt Tower Raikou and Entei will be wondering the Routes of the game that include tall grass. They will only stays for 1 Round in any battle and then they flee but they will retain any Status and damage you have done to them. If have a Pokemon that has an ability that will keep them from running then bonus. Otherwise work them down one attack at a time. They change Routes every time you do so your best bet is to simply going back and forth between two routes (I use Routes 36 & 37 below Ecruteak) until you see in the Pokegear that they are in your area. Then head into the grass and capture them.
Legendary Pokemon - Raikou & Entei