Welcome to Wuhtu, where every week is Sharpedo week a whole new region of the Pokemon world a la Kanto, Johto, etc.
There are the overt similarities, of course: Pokemon roam, trainers battle, and all that jazz.
The differences though, are what make Wuhtu interesting.
Wuhtu is a world that I created for a game of PTA (now PTU) on the GitP forums. It is an ever expanding work in progress that grows and evolves just like the players who explore it and the GM who tries his best to run it.
on iPhone, iPad, AppleTV, PC. It's free.