This is a facility that exists in every main Pokemon game. It is dedicated to the studying of Pokemon. The Trainer's School offers a range of skills for budding trainers, including the effects of poison/paralysis/sleep/fire/ice and other status affecting moves. In the buildings there are other trainers that are more than happy to give you some advice on raising, training and battling Pokemon.

Diamond and Pearl

Two kids will have an Abra that only knows Hidden Power. If you beat both of them, the boy one will give you TM10 Hidden Power