If you prefer doing it yourself, instructions on how to download and install the update on your Amazon Kindle follows
- Determine the current software version on your device
- Go Home
- Select Menu
- Select Settings
- The Kindle version will be at the bottom of your Settings screen
- If you see an earlier version than 4.1.0 please proceed.
- Download the Amazon Kindle 4.1.0 software update
- Transfer the update file to your Kindle
- Turn on your Kindle and connect it to your computer
- Drag and drop the update file from your computer to the root of your Kindle drive
- Once your file has completed transferring to your Kindle disconnect it from your computer
- From the Kindle Home Screen, press the menu button
- Select Settings
- Press Menu button again
- Select Update Your Kindle (This option will only be available if you have an older version)
- Select Ok when prompted to perform the upgrade.
- Kindle will restart and inform you that Your Kindle is Updating.
- One the update is complete your Kindle will restart for a second time
- Go to Settings
- Your Version should now show 4.1.0
- Improved reading font that is higher contrast and crisper so that you can enjoy a paper-like reading experience.
- Parental Controls that allow you to restrict access to the Experimental Web Browser, Archived Items, and the Kindle Store.
- Support for books with complex layouts and formats with Kindle Format 8.
- Support for children's books with Kindle Text Pop-Up and comic books with Kindle Panel View (which allows you to read a comic book panel by panel). Books that support these features will be available in the Kindle store over the next few weeks.
- Dictionaries grouped into a collection in Home and Archived Items called "Dictionaries" for better organization.
- Improved table and image viewing (panning and zooming) on supported titles.
source - Amazon