First you beat the eleate four then go to your house and press A on the tv. You will have a choice between red and blue. Red is Latias and Blue is Latios. If you still have your master ball that is good. You should find it basically anywhere. One you do find it though, it will run away after one turn unless you have a Pokemon with meanlook. So use your master ball and you should catch it. If you don't have a master ball than use mean look and try to catch it. Also have a level 50 or under in the start of your party.
Latios cannot be caught in Pokemon Diamond. You must get one off the GTS if it is in your Pokedex, or you must migrate it from Pokemon Ruby, Pokemon Sapphire, or Pokemon Emerald.
No you cant catch Latios in Pokemon Colosseum. You can only trade it in from your Ruby or Sapphire game in to the Colosseum game and that's the only way you can get it.
there are ezactly 13 including the other 3 of deoxyis forms
No you cannot catch Celebi in Pokemon Emerald.
No I don't believe you can catch a ledyba in emerald
You can onl catch LUNATONE in SAPPHIRE but you can catch solrock in emerald
yes you can catch a Manaphy on emerald. (if you have a game shark)
Yes, You can catch Groudon in Pokemon Emerald.
You can't catch one in Pokemon Emerald.
You can't catch it in Emerald. T-T
you can not catch it
you cant dummy