Legendary Dogs Guide
Pretty simple but might as well if people are confused...
Moving on, Entei/Suicune/Raikou can only appear AFTER you get the National Dex, your starter that was chosen defines the starter (by their weakness).
Bulbasaur = Entei
Charmander = Suicune
Squirtle = Raikou
This is similar to Latios/Latias in R/S/E, they thrive around KANTO (not the Sevii islands). The best way to do this is have the following.
X1 MASTER BALL (if not, you're stuff UNLESS you do the cloning glitch in Emerald, google that, I'm not bothering on that part).
A Level 50 Pokemon that can Sleep (Paralysis is OK as well) and also Quick Claw (just in case).
Heaps of Max Repels (I mean HEAPS).
It is going to be a pain finding them without knowing where the hell they are. In this case, try and find a route that links to another (if not then it's going to be a bit more difficult). Make sure your 'Level 50 Pokemon' is in the first slot. Activate Max Repel, walk through the grass, if nothing for some time, go to the other route, do the same thing, then so on... Eventually, the dog will appear. BTW, the dogs are all Level 50.
It will be pointless using Mean Look, etc. On Entei and Raikou due to it's Roar, though with Suicune you will be fine. Otherwise I'm not sure. If it flees, don't worry it records the areas in the Pokedex every time you alternate Route/City/Town.
Well, good luck catching it!
Quick Guide by Feenicks
NOTE - This is all my work that has came purely out of my knowledge, I never intend to plagiarize peoples work.
Added by: Feenicks Dec 19th 2008, ID#12527