Like many rumors has said, now you can began download iOS 4.3 IPSW Direct Links, this is the nice option for iOS user that have limited speed. Directly download from iTunes for same user is really bad and need more longer time.
To fix this problem, I choose to download iOS 4.3 ipsw manually and began update. If you need guide how to update iOS 4.3 ipsw manual, you can follow that guide.
This is better option, because Direct Download Links iOS 4.3 Firmware Update (ipsw) we can use this files again in the future
And here is the iOS 4.3 IPSW listed files in many iOS family
Please notes, you need latest iTunes 10.2.1 to update your iOS device into iOS 4.3. If you have good or fast internet speed The firmware update can be downloaded from iTunes software.