There are two cover versions around at the moment but I prefer this one by M Ward from a few years ago (it doesn't seem to be on iTunes, probably because the artist is precious about it).
Here's Hi-Fi, a really good M Ward original (iTunes).
And here's a little-known Bowie track, It's Gonna Be Me (Amazon).
I read somewhere that John Lennon came on board late for Bowie's cover of Across The Universe, so they had to lose something from the Young Americans album to make way for it, and this was the track they lost. You have to be a really great and prolific songwriter and artist to leave out tracks this good. See also Sad Eyes by Bruce Springsteen (iTunes).
(update of post originally from 15/08/07)