You can view Google Street View through the Google Maps app. The app is available for free on Android and iOS devices through the Google Play store and Apple's App Store, respectively, as of 2015.
To access Google Street View, simply type in the address that you want to view into Google Maps. If Street View is available for that address, an image of the address entered pops up in the lower left corner of the screen. Click on the preview picture to switch over to Street View mode. This process is the same for both Android and iOS devices.