Vía de la Plata in app form for iPhones, iPads and Droids. The app
guide has +400 entries and nearly 4,000 photos covering the trail segments, tricky spots, towns along the routes, points of interest, restaurants and lodging. There are also maps that are scrollable offline. In 2013, Vía de la Plata won 3rd place for Best Travel App in the Society of American Travel Writers - Central States' annual writing competition.
I typically walk a portion of the trail annually and update the guide, so it's quite current. But the app also includes a Comments section so users can update entries as they walk. So far, peregrinos are regularly adding useful information for their fellow hikers, which is great.
The Droid link for the guide is: