It's no substitute for reality, of course, but it's not bad.
For newbies, start here (or the satellite view), zoom in with the +/- buttons (drag to recenter), then drop the little yellow Streetview man where you want to walk. Drag your cursor left/right for panorama views, and (especially at Machu Piccu) up and down to look up and down.
Related news today:
This summer, under pressure from Unesco, which has repeatedly threatened to add Machu Picchu to its list of world heritage sites in danger, the Peruvian government has brought in measures to control the flow of tourists.More at the link.
From 1 July, visitors will only be able to enter the site with an official tour guide, and tickets will grant entry for a specific time period, either a morning (6am-noon) or afternoon (noon-5.30pm). Guides must be licenced and group size will be limited to16 people. Visitors must also follow the defined routes around the site, a change from the present setup where it is possible to explore relatively independently and stay the entire day.