Who sings "May You Stay Forever Young" in the new Pepsi ad?

Bob Dylan and Will.I.Am

OK, but where can I find the real upbeat version found in the commercial? Or even the Will.I.Am. Version?

I doubt if you will find it as a release yet.
Pepsi commissioned the remake for this year’s commercial.

Maybe check with the studios mentioned in the article above?

the upbeat version is an alternate take of Forever Young that is on Planet Waves

See ithere: http://www.time.com/time/specials/packages/article/0,28804,1874549_1874552_1876155,00.html

How can I load an MP# download on my ipod?

Click on the above link to play it and record it into garage band (make sure you go into controls and click off metronome or you’ll have the annoying click, click, click of it in your recording), edit a little dead air in the beginning and end and import it into itunes.