Frog Find is a free Android application for frog identification, featuring images, descriptions, habitat, distribution maps and now some audio files.
The app has been around since April 2013 and has since been found very useful by a lot of enthusiasts in the field, but one major feature missing was info about calls. This new version claims to address that issue by adding some audio files. It also features updated common & scientific names.
Note: Though it covers most of the commoner species, the app is not a complete guide in itself, but an add-on to Dr. KV Gururaja's book.