Today Apple has released iOS 4.3.1 for the iPhone, iPad and 3G and 4G iPod Touch models. This is just a minor update to fix some bugs; and remember: don’t update if your iDevice is unlocked and is currently jailbroken.

To update to this iOS , simply connect your device and open up iTunes and you should see the message you all know about saying that there is an update available.

iOS 4.3.1

However,  if you wish to download the iOS firmware or IPSW here are the direct links(official download from Apple).