Amazon have updated the Kindle app for iOS. Version 3.2 adds adjustable margins, highlighting options and improved control over brightness.
The app is free from iTunes
New Features in 3.2:
• Adjustable Margins (iPad): Choose from three layouts for your preferred reading experience.
• Rapid Highlights: Quickly mark important passages for handy reference later.
• Improved Brightness Control: Refined the brightness slider to be more responsive and optimized font hues for better viewing.