Simply by a MJ album via iTunes in the next few days and you will get a code which you can redeem on Ticketmaster's website to then be able to buy 2 tickets for his tour.
Basically Apple bought 2000 tickets for which you can buy a maximum of 2 each and then flog them to people who buy their product first. Genius. Love the tie in. Afraid it didn't work on me, as much as I loved his music, I can't think of anything other than the image of him performing his greatest hits on gig number 37 with an oxygen mask attached.