I said this on another thread (I think it was first shiny), but I'll say it again
The first shiny I ever saw was in FireRed, and I beat it on accident. It was a Zubat and I found it in Mt. Moon looking for a Clefairy.
I didn't see another one until about a week ago, in Black, where I caught a shiny Joltik training for Mistralton gym in Chargestone Cave. My first caught shiny EVER!