The Battle Tower, and that's only after you get the National Dex. Wrong place to ask, too.
[agelimit]competent competitors[/agelimit]
Ichida, the Zealous Blue Partizan
Pearl Battle Record: 105-26
Battle Style: 6v6 Lv100 Singles, No Hacks, Ubers or Legendaries

To gamingly entertain the crap out of you. Yes, I said 'gamingly.'