Amazon has released an update to its Kindle app for the iPhone, iPod touch and iPad adding an in-app dictionary, book searching, and iOS 4 improvements. Kindle 2.2 now provides the ability to instantly lookup selected words in a 250,000-entry built-in dictionary as well as searching for words on Google and Wikipedia from within the app. The update also brings the ability to search inside books to the iPad and improves the in-book search introduced to the iPhone and iPod touch in the previous update. The latest version also brings iOS 4 Fast App Switching on multitasking-capable devices and other iOS 4 related bug fixes. Kindle is available from the App Store as a free download.