Start your iTunes. iOS 4.3 is here.
Apple just released iOS 4.3. You can download and install it now from iTunes. The biggest feature in iOS 4.3 is personal hotspot among several other improvements. You can read all about the details on iOS 4.3 here.
Initially Apple said they would release iOS 4.3 on Friday. The iPad 2 will go on sale with iOS 4.3 installed this Friday. Maybe Apple wanted to make Friday an iPad 2 day and not have iOS 4.3 released on the same day.