Microsoft has officially released Internet Explorer 10 to the public. IEX can install one of 2 ways. Either by downloading and installing the software or via the Windows Update. IEX is considered a recommended update, so it may install automatically when windows updates.
If you have purchased a computer with Windows 8 or have purchased the Windows 8 upgrade, you have IEX already installed.
You will need to be aware of changes to Internet Explorer if this is your browser of choice.
If you still are using Windows XP, you will not be able to install IEX. you will need to update to Windows 8 to install IEX.