As I've got an HTC phone which uses the Android operating system, I was interested to see Amazon have a handful of free applications available. I knew about the Kindle version already, but there are a couple of other useful ones too.
You can see more details here:
Free Amazon Apps
- but basically there is the Amazon Mobile app - which is just a version of the store, then the MP3 store and library. Also there is "Audible" which is for downloading audiobooks, and lastly a useful feature for film-lovers, the IMDB app. This can show you local film and TV listings, as well as search their online database and see trailers too.