Originally, The Plain White T’s, whose preferred punctuation upsets me, released a simple and catchy song called Hey There Delilah
Of course, writing a simple song that sounds like you’re stalking someone which mostly requires a guitar is just asking for someone to parody it, so:
Via ElevenWords we have Hey There Delilah
and via The Fump comes Robert Lund’s better parody Re: Your Song About My Client Delilah.