Amazon has shown some love to users of its Kindle app for iOS devices by providing an update that adds a slate of new features.

Version 3.6 should definitely please voracious book highlighters. Instead of the single highlighting color for day and night reading, users can choose from one of four options to mark that important book passage.

The update also adds some actions after a book has been finished. Users can share what they’ve read on Twitter and Facebook, and then rate and write a review about the title. The app will now automatically show other books that might be of interest, and allow users to add them to a wish list.

Finally, the brightness settings in the app will be saved across device sleep sessions.

The Kindle app is universal and designed for both the iPhone/iPod touch and iPad. It can be downloaded in the App Store now.

Even though you can’t purchase books directly from the app, I’m pleased to see that Amazon continues to improve the Kindle experience on iOS devices. After the update late last year that added the X-ray feature, and today’s improvements, I’ve resolved not to open iBooks anytime soon.

If you’re looking for similar apps, take a look at our AppGuide of Book Apps for the iPad.