How Soon Is Now? - The Smiths
good song.
though technically that song never asks that exact question, which makes it a candidate for a similar potential thread: songs with a title not sung in the song.
(closest thing to the title in the lyrics "when you say it's gonna happen now, what exactly do you mean?...see I've already waited too looOong....")
For another:
Who can it be now? (Men At Work)