Dialga, Giratina, Heatran, Mespirit, Uxie, Azelf, Regigigas, Rotom, Cresselia,
well in Pokemon diamond it can be possible to catch all of them but the easiest ones are dialga,shaymin,mesprit,and the other two lake Pokemon i cant remember the names.
no
use the Pokemon locator.
Giratina is a Legandary Pokemon of the Sinnoh Region.It is said to be in the Distortion World.You can catch it normally in Pokemon Platinum,Pokemon Diamond, or Pokemon Pearl.To catch it in Heartgold or Soulsliver,You need a special Arceus.
Tyranitar
After you beat/catch garintina in diamond you could keep training or just keep fighting the pokemon league. Also, you could go catch more legandary pokemons.
giritina, palkia and dialga
when the three legandary pokemon of the lakes are captured the you have to go to the galactic hq in veilstone and get through it then when you beat the boss he gives you a master ball. Hope this helped :D
in unova, about 7 legandary pokemon. in total, about 28.
platinum:arceus leafgreen:mewtwo silver:lugia emerald:rayquaza
you can't breed your starter pokemon cauz they are like the legandary pokemoni