Shouldn't you have several of the letter? It's not just one, if what I'm thinking it is is what it is.
Now it's on to the song title...

Edit: I figured it out, but I don't want to answer it here so that other folks get a chance to solve it. Suffice to say, good job! That was a good one.

It's The Shins - Saint Simon

Here's mine, the filename might help as a clue. Also, some of it relies on a little knowledge of social terms, but not necessarily.

Nobody?
Ok, a clue:
acaliskey = a calendar is key