Apple on Wednesday released iOS 4.3, the promised update to its mobile operating system.

[ad#Google Adsense 300×250 in story]First announced during last week’s iPad 2 event, iOS 4.3 wasn’t supposed to be released until Friday when the iPad 2 ships to customers. However, Apple released the operating system a couple of days early.

iOS 4.3 has plenty of new features including the Nitro JavaScript engine, which will increase Safari Web browsing speeds, iTunes Home Sharing, and enhancements to AirPlay.

One feature that many people are interested in is the Personal Hotspot used for sharing the cell signal over Wi-Fi.

Many iPad owners will enjoy a change in iOS 4.3 that allows them to use the hardware switch on the side of the device to lock the orientation. Apple changed the button to mute the audio in a recent update, but the feedback from users convinced the company to add a preference allowing users to choose between mute and orientation lock.

iOS 4.3 can be downloaded by connecting your iPhone to your computer and clicking Check for Update in iTunes.