Now, Pokemon trainers from all over the world travel to towns with Gym Leaders to challenge them to battles. When a trainer beats a Gym Leader, he or she receives a badge to symbolize his or her victory. It takes eight badges to gain entry into the Pokemon League and compete for money, fame and the title of Pokemon League Champion.
Team Galactic - Previously run by Cyrus and bent on destroying the universe and remaking it with their leader as a god, Team Galactic is now trying to repent for its former wrongdoing. A little less than a year ago, Saturn took over the role of leader of the organization. The team is still dedicated to finding limitless energy, but their focus is less on world destruction and domination and more on eco-friendly energy.
Of course, there are many members of Team Galactic, both new and old, that feel the new course of the organization is not nearly so glamorous and not in keeping with their ideals. The team has split, and although both call themselves Team Galactic, the fight for dominance over the organization is still ongoing.
The Galactic building in Veilstone City has been boarded and cemented up due to toxic energy from the experiments conducted there. The team now makes the building in Eterna their headquarters.
Team Rocket - Originally based in Kanto and Johto, Team Rocket is a criminal organization similar to the mafia and yakuza. It was started about 80 years ago in Celadon City with the simple goal of controlling the city, but as leadership of the family was passed down through the Adamo family, its influence expanded… as did the scope of its goals. Under its current leader, Giovanni, its current goal is world domination.
Team Rocket is primarily motivated by greed, and most of its profits come from the illegal trafficking of stolen and unethically captured Pokemon. They also run casinos and other shady enterprises. Of course, organized crime is only the surface; Giovanni is known to employ scientists who perform twisted experiments on Pokemon and, according to some rumors, humans.
The organization seemed to crumble four years ago when a young trainer took it down. Giovanni disbanded the organization and disappeared for a few years for the purposes of training. Leftover Admins attempted to contact Giovanni for the purpose of resurrecting it in Johto, but their attempts were also thwarted. For a few years, no activity has been reported from the Team outside of wild rumors and a few hoaxes, and it seemed as though it was gone for good… until recently. There are rumors that it’s attempting to gain a foothold in Sinnoh, and only time will tell if they’re true or not…
Professor Rowan - Currently a resident of Sandgem Town, Rowan is the foremost professor in the Sinnoh region. He meets most of the starting trainers from the western Sinnoh area and most of the eastern area as well. He hands out the starters Turtwig, Piplup and Chimchar; however, he can be persuaded to hand out starters from the other regions or occasionally common Pokemon to new trainers. The best way to do this is to bring cake, cookies or other sweets, because he has quite a weakness for them.
The professor seems quite gruff, but is actually very caring towards trainers and Pokemon.
PokeNet – PokeNet is the latest fad in Sinnoh. It’s a device similar in design to a cell phone that allows users to access a worldwide message board (also called PokeNet) anywhere in the region. They were first manufactured as an expensive, updated form of the Pokegear in Johto a few years ago, but after they were brought to Sinnoh, prices dropped enough that they became accessible to practically everyone.
The PokeNet allows users to post text, audio, and limited visual content. It also permits users to transmit private messages to other users and filter posts to certain groups.
The Pokemon World - For players who are completely unfamiliar with the franchise but are still interested in being a part of Pokeology, we have a brief rundown. The Pokemon world is a collection of regions where intelligent animals called Pokemon live in harmony with humans.
At age 10, children can choose to pick up a Pokemon from a local Pokemon professor and begin their quest to be a Pokemon trainer or coordinator. Trainers concentrate mostly on battles while coordinators concentrate on competitions to show off their Pokemon.
Older children and adults can even become Pokemon rangers, who temporarily befriend wild Pokemon to fight natural disasters, or researchers, to learn more about Pokemon.
Bulbapedia has more detailed information about the Pokemon world.
Serebii is mostly concentrated on game mechanics; however, it has some excellent information on Pokemon moves and stats as well.