Home Sharing is set up in Settings -> iPod -> Home Sharing
I don't know what you mean by a "redesigned" App Store or keyboard. The updates that iOS 4.3 includes are listed here:
http://www.apple.com/ios/
The App Store itself was updated a couple of weeks ago to now show “Installed” rather than the app’s dollar value, and then to display the message “You have already purchased this item. To download it again for free, select OK.” Those should display in the Updates page when you have updates available.
I don't know of any other changes to the App Store, and I haven't seen anything about changes to the keyboard in the release version of iOS 4.3. Not all items that were in the seed versions of iOS 4.3 were included in the release version so perhaps you're referring to something you read about earlier that was not included in the release.
The Noteworthy font replaces Chalkboard in the Notes app, and only there. That should also be available in Settings -> Notes.
Regards.
Message was edited by: Dave Sawyer