It's one of the news articles from this morning. You have to download it yourself from a link then do a trick or two to install it. Quite easy as long as you read the directions (and take the .zip off the filename before you install).
the only people having trouble are the ones who don't pay attention or read. Its very easy and as simple as holding down the option (shift for windows users) key when you click check for updates then point to the file you downloaded. iTunes does the rest...