SecretLove--I'm like Lindsey. I can play piano by ear but can't read music. (Sadly, though, I certainly cannot play guitar--Stevie would easily out-strum me laugh
It's good you're learning how to play their songs. Someone on The Ledge sold me a piano sheet music book of FM songs.
What Luminol says about sheet music is correct, particularly in the case of this band. The playing and recording comes first; any notation is done later by companies that do that sort of thing. Rock and roll musos like this band do not need or use sheet music for their songs. If anyone did it would be Christine, but lets face it--her musical structures aren't exactly Wagnerian.
But the general topic of Landslide as a piano song v guitar song is an interesting one.