Getting to Machu Picchu is an adventure in itself. Typically you will start your trip from Cusco, in the Peruvian Andes. There are roundtrip flights from Lima to Cusco several times a day, mostly in the mornings. Flights will vary but be approximately $150 roundtrip (as of 1/01). Once you arrive in Cusco be warned that many get altitude sickness right away. Cusco is 13,000 feet above sea level. From Cusco you will be able to take a train to Aguas Calientes, about a 3-hour ride, depending on which train you take. Depending on the weather and the season, you may have to take a bus half way to Ollantaytambo and a train the other half. The trip still takes about 3 hours.
You also have the option of taking a helicopter from Cusco to Aguas Calientes but be ready to pay premium.
Most people will visit the ruins as a day trip, returning to Cusco in the evening. Be prepared to alter your plans as need be. On our trip up on the bus, we didn't quite make it to Ollantaytambo where we had to catch the train for the remainder of the journey because there were protests going on in the center of that town and the military riot control unit had been sent to retain control (see photo). In our case all the passengers on our bus had to walk back a ways to a point where we could walk the last couple miles along the railroad tracks into this town (see photo). We were able to safely make our connecting train and continue on up to Aguas Calientes. Once there, we had arrived at the town that serviced Machu Picchu, which was perched a couple thousand feet above us on the mountain. From here we boarded a bus that took us up the mountain on a road that was rough and bumpy. The ride to the entrance of the ruins takes 30 minutes and it's all zigzagging switchbacks up the mountain. Some turns are so tight that the driver has to drive within inches of the precipice. No rails of course. Not for the faint of heart. If you are afraid of heights, don't look out the window.