goal machine

Well, your'e half way there, what you need to do now, is go to the Sky Pillar. To get to the Sky Pillar, you must fly to Pacifidlog Town (I think thats how ya spell it), and then use swim on the right hand side. Keep swimming up top of the screen, until you come to an opening in the rocks, then find your way around the rocks, until you come to some land. Make your way through this small like, path. Then you will come across a very tall building, enter the building, and try and make your way through the building as quick as possible(You make be held up due to the fact that it's basically a maze). At the top, you will find Rayquaza, use strong Pokemon, not too strong as he is at level 70, I recomend using an Ultra ball to catch him. Now the next one, is Latias.
Unfortunately there is no method for finding Latias as he is found randomly like you would find a regular pokemon. Once encountering Latias, I would recomend you use your Master ball. If you've already used it, then you must get a Pokemon with mean look, so Latias won't flee. The good thing is, is that if Latias does flee, than you can now locate her, using the area device on your pokedex. As for Latios (the Latias counterpart) you have to trade it from either Ruby, or Emerald.