Where can you capture Latias and Latios?

Latios and Latias only came out since the third generation of Pokemon.

In Ruby, Latios can be found roaming Hoenn. So that means you can find him in a certain time when you are in the same area as him. You can find Latias in the southern islands.

In Sapphire, Latios is in the southern islands and Latias is roaming Hoenn.

In fire red, leaf green, pokemon colosseum, Pokemon XD, Pearl, Diamond and Platinum, Latias and Latios does not appear so you have to trade latios or latias from a different version.

In Soul Silver, Latios is roaming Kanto and Latias is in Pewter city.

In Heart gold, Latios is in Pewter city while Latias roams Kanto.