We're planning our trip to Peru and Machu Picchu for May 2014 and I read on a bunch of sites that the government ticket website would have the rates and tickets for 2014 available only the last week of December. Happened to check today just for kicks and they're up and available! You can buy tickets at the government site at http://www.machupicchu.gob.pe/
I did have the same issue everyone talks about with my Visa card from the US (my bank does not offer "Verified by Visa") and so had to get on the line with Visa before I hit the "Pago" button so they could approve the purchase as it came through. No problems doing it that way and I printed out my tickets immediately after the charge went through.