Did we ever find out how the twins knew the results of the Quidditch World Cup thingy?

Considering that no one has answered your question in a month, I'd say nobody knows. Sorry! Maybe you could send your question to J.K. Rowling on her fan email or something? Sorry, cuz I don't know either.

I'm pretty sure with all the thigns the twins have done, learning quiditch results is nothing. They could've asked in Hogsmede, they could've reda the prophet, mailed their parents, talked to a friend or teacher.

Do you mean like knowing beforehand, for their bet? I always believed it was just a really good guess.