Machu Picchu is beautiful. It takes your breath and stirs your mind. Anyone passing through Cusco should try going and even better if you've got the means and time for the Inca Trail (though I'd recommend going from Choquequirao then). It's also the Ministry of Culture and the departmental government's most lucrative tourist cash cow and they milk it. You're made to think that the only way to get there is via a tour package that begins and ends with a gringofied train serving fine western cuisine and cheesy Andean folk shows that costs you an arm and a leg of at least US $100. Most also encourage you to prolong the experience in the theme-park hotel town of Aguas Calientes, a.k.a Macchu Picchu Village, near the site. To people of the area, these exemplify the prostitution of their heritage to satisfy the foreigner while preventing access to those to whom it belongs. I strongly recommend taking the bus route instead. You'll save a lot of dough, get to travel through incredible landscapes, meet charming people from the Sacred Valley and probably take one of the most memorably pleasant day-hikes of your life. Machu Picchu means 'old peak' in Quechua, try to pronounce the two c's like locals do as "piK-Chu".
Light blue = bus terminal to Sacred Valley; red = Ministry of Culture; green = INTEJ / ISIC card; purple = the central market, a cheap hostel on cuesta San Blas street if you're stuck, the amazing Centre for Traditional Textiles of Cusco on avenida del Sol.
To access the site of Macchu Picchu you'll need to buy an entrance ticket from the Ministry of Culture (no longer Instituto Nacional de Cultural). You can purchase it online here (though the website doesn't often seem to work), from a booking agent who will likely insist on selling you a tour, or directly from the MoC's office in Lima or in Cusco at 238 avenida de la Cultura (red dot in the map above). Mine and others' experience is that you can go early in the morning (7-8am) the day before your planned visit and should still find available tickets. The normal price is around 130 soles but students pay just 75/s. To get the student price, you will need an ISIC card. It can be purchased for 30/s. from INTEJ on the north side of the Plaza de Armas (green dot).
When you buy your entrance ticket, you'll get to pick one that includes additional access to a trail going up the Wayna Picchu or one with access to a trail up Machu Picchu Mountain. Wayna Picchu is the pretty sugar-loaf-like mountain hugging the main site which you see at the back of most pictures. It goes up around 200m in altitude and leads you to a few more small archaeological sites (though getting to the Templo de la Luna involves a long loop below the main site). I've heard that it's fun, somewhat tough and that you get good views, but it's crowded. You also have to be within the 300 visitor limit that they let in every day. Machu Picchu Mountain involves ascending 400m of altitude to an old Inca surveillance outpost that gives you a plunging view of the site and also places you above the ring of mountains framing the Vilcanota river valley below allowing you to see the surrounding snowy peaks and sacred Apus. The second sounds more attractive to me. My friend and I chose it and enjoyed a serene, solitary, challenging hike up. Unfortunately we went at the height of the Andean rainy season and found ourselves surrounded by thick mist once at the top. The best time to go for clear skies is May to October.
Red = Cusco / Santa María; orange = Santa María / Santa Teresa; blue = hidroeléctrica / Machu Picchu.
Once you have your ticket and are ready to go, you can start your trip at the bus terminal in the southwestern central area of Cusco along calle Antonio Lorena from where all transportation routes through the Sacred Valley begin (sometimes it's called terminal Santiago, it's on both maps). Ideally you leave the same day that you buy your entrance ticket, then sleep overnight closer to the site in order to wake up and hike before dawn. Since the overall trip is short, I recommend leaving your main gear with a hostel you trust in Cusco.
The first bus to catch is the long 6-8h 200km leg to Santa María that costs 15/s. The bus that gets you there has a final destination of Quillabamba. You'll first go above Cusco, then plunge into the Sacred Valley, then go back up the other side over another high pass into a valley of pine tree forests lined with snowy peaks until you get to tropical low-altitude Santa María.
When you step off in Santa María, there's a good chance that you'll be swarmed with offers to take you to the next checkpoint of Santa Teresa and the hidroeléctrica (the hydroelectric dam where the walk starts). Stay alert for scams ("there's been a landslide, you have to stay the night here") and remain firm when negotiating: it takes 45min to 1.5h by shared taxi and should cost 10/s. a person all the way to the dam. Both Santa María and Santa Teresa have ample lodging options, though I would recommend staying in the second to be as close as possible to the site on the next day.
The hidroeléctrica is the starting point of the 2-3h / 14km hike to the site. For most of the way, you just walk along the train tracks that go to Aguas Calientes. A few kilometres before though (after 9km), you'll cross the road that connects the town to Machu Picchu. Here you should turn right to hike the remaining stretch up 400m of altitude on a well-built stone trail through cloud forest straight to the site entrance. Then just hand over your ticket and enjoy!
See my post Inca Masonry for a few more rainy photos. Thanks to my friend and travel partner Alexei for a few of these!
On the way back, the formal buses to Cusco from Santa María are poorly scheduled and usually arrive quite full from other towns. A better option is to flag down one of the large vans offering informal private transport that pass through every hour by the military control post. If they have free seats, these faster vehicles will save you a couple hours of time and you'll still pay just 20/s. The restaurant 50m next to the stop where you'll probably wait serves good food.
This route left me very aware of how isolated Macchu Picchu must have been while inhabited, and now its power to fascinate and attract people from all over the world. The walk to and from the site has you crossing paths with large numbers of travellers, all calmly advancing towards a place that they've long dreamt of. All the while, you circle the site from below along the Vilcanota River, the sacred stream on Earth that here mirrors the celestial river of the Milky Way in the sky at night (the Mayu in Quechua). You wonder in the site's majestic extent but also its diminutive integrated presence in the middle of these jungles and the enormous alive mountain range that are the Andes.