If you don't fancy walking the Inca Trail, you can always take the train to Machu Picchu.
There are three choices for the route between Machu Picchu; to travel on the Expedition (formerly Backpacker), Vistadome or Hiram Bingham service. As you would guess, the Expedition service is the cheapest with the Hiram Bingham the most expensive, although they all follow the same route.
The Hiram Bingham service is designed to enable passengers to visit Machu Picchu in a day, departing Cusco in the morning (brunch served), before arriving at the Citadel for an afternoon visit, before rejoining the train for a gourmet dinner on the return journey to Cusco.
PeruRail has recently opened a station at Urubamba, with services to/from Machu Picchu. Visit the PeruRail website for more information.