Chris McElligott has posted a high quality AAC file (1.5MB) of the song created by John Mayer and arranged by Apple CEO Steve Jobs onstage at Tuesday’s Macworld Expo keynote. The song was created with Apple’s new GarageBand music application. McElligott has also posted a downloadable video of Mayer’s performance (4.3MB) as well as the entire GarageBand segment (56.6MB) from the keynote.