What does 話って mean and how is it used?
I found it as a question in the following:

"話ってなんだい？"

Question

What does 話って mean and how is it used?
I found it as a question in the following:

"話ってなんだい？"

Answer

Usually this phrase is used to respond to someone who has said “I have something to tell you.” (話があるんだ＝あなたに話したいこと[or 話さなければならないこと] がある。)
“話” = "あなたに話したいこと（something to tell you）”

「話ってなんだい？」means "So what is it?" 
(You can even omit なんだいfor this. )

Hope it makes sense:)