That's right! If you read the title you will now know that Microsoft has started to send out the Mango update to phones.
The leaked date actually came true in the end and Microsoft themselves announced that Tuesday September 27th was indeed Mango release day. But before you go off to quickly hook up your phone to your computer there are a few tid bits of information to go through as to why you may or may not have been alerted by your carrier to tell you your update is ready.
First off Microsoft has only released Mango to 10% of the Windows Phone population thus far, the reason behind this is they say its a delicate process and they would rather take there time then try to push it out to everybody all at once and end up messing things up.
Do not fear though eventually everybody will get the update its just that some people may get the update today, tomorrow or sometime within the next month.
If you are impatient though you could always use Microsoft's Where's My Update Feature.