in pearl and diamond you have to swim there from sunyshore
EDIT: The Pokemon League's Pokemon are about level 50. If you're pokemon are level 45+ you will be fine but if they're below level 40 you will have a hard time to beat the Pokemon League. I would have told you more but that would spoil the fun for you. :)
In the Pokemon league.
That depends on what league you are talking about.
The Pokemon league is where all the elite 4 are(they have strong Pokemon)
the best Pokemon for the Pokemon league is definetly latios
Yes, you can use any Pokemon in the Pokemon league.
Pokemon battle arena is better than Pokemon league.
surf around the pokemon league
The Pokemon League isn't in a city. The Pokemon League is on a place of its own. It is above victory road, and is east of Blackthorn city.
technically, when you beat the Pokemon league, you become the champion. but you cannot really fight as a part of the Pokemon league
No, there is no short cut to the Pokemon league building in Pokemon pearl.
in the Pokemon league. Yes, it is but you have to go through a cave to get to it. Look on your map.