Just installed the GM seed of iOS 4.3 on my iPad. As announced in the recent iPad2 release, the new version has two new options:
- Set the side switch (the one above volume key on the right side) functionality: Mute or Lock Rotation.
- Sharing your iTunes library with any iOS 4.3 device (within the same network)
The multi-tasking gesture function that was originally announced to be a developer preview feature, now looks to be making its way to the final release also.
Here is the option to set the 1st feature:

The multi-tasking feature basically lets you switch between open applications with left/right swipe and see the open application list with ‘swipe up’. You can still double-press the Home button for the latter.
Now the 2nd – Home Sharing: This option as you probably know, lets you stream your iTunes library on your PC or Mac to other iOS 4.3 devices in the same network. In order to do this, you should first enable Home Sharing in iTunes (I did this in iTunes 4.2/Windows 7):

You will also be required to login with your Apple ID when you turn on Home Sharing. Once done, you can enable Home Sharing on your iOS 4.3 devices and see the shared iTunes library; you should again login on the device with the same Apple ID used for Home Sharing in iTunes. Let me repeat: your iTunes host PC/Mac and iOS 4.3 devices should be on the same network.

After providing the same Home Sharing Apple ID, open your iPod application to view the shared library:

Select your shared Library and you all set to enjoy your iTunes home sharing/streaming!! (the albums you see below are from my iTunes library on my Windows 7 box)

I am yet to install the 4.3 GM on my iPhone. Not expecting any surprises…