AirPlay Enhancements: the wireless technology that lets you stream content from your iPhone, iPad or iPod touch to your HDTV via Apple TV.
iTunes Home Sharing: Now you can play your entire iTunes library from anywhere in the house. If it’s on your Mac or PC, you can play it on your iPhone, iPad or iPod touch over a shared Wi-Fi network.
iPad Side Switch: Customise the switch on the side of your iPad to lock the screen rotation or mute the volume. So you can lock your iPad display in landscape or portrait. Or quickly go from volume on to volume off.
Personal Hotspot for iPhone 4: On the road, in an airport, at the park — now you can take Wi-Fi with you wherever you go. Download iOS 4.3 on your iPhone 4, and the next time you find yourself without access to Wi-Fi but in 3G territory, enable Personal Hotspot and share your mobile data connection with your Mac, PC, iPad or other Wi-Fi-capable device.
Visit the Apple website for more information.