It is not "out already"..... it is beginning to roll out now and will likely be a very slow process so some patience will be necessary.
As best as I can determine, right now, Microsoft is not offering another resource for the update that will allow anyone to circumvent the normal Windows Update process for this particular update.
I'm relatively certain that at some point in the very near future, they will likely make the ISO available for download through another source.
Try going to Update Status and click "Learn More". It will take you to Windows 10 update history. When there it gives you the option to download the Windows Update "Anniversary Update Now"!!
A link:
https://support.microsoft.com/en-us/help/12387/windows-10-update-history?ocid=update_setting_client
Hope this helps. I too spent quite a bit of time yesterday ( 08/02/16) checking for the update using the Windows update feature only to be told my system "IS" up to date.
I wanted to do my Big Box ( about 5 year old desktop) first as it had the most problems going from Win 7 To Win 10. Turned out the upgrade turned off my external Wi-Fi before the update was completed, had the EXACT same problem with the "Anniversary Update". Got smart after it downloaded the update I disconnected the Wi-Fi
BEFORE staring to install the update. After that I now have the Anniversary update installed and working "fine"! Some of the "new" stuff I don't use and some were good. Biggest thing I liked was under Update Status, the restart options. If you have Windows update set to install overnite and the update requires a restart you can set it to restart using your credentials to complete the update!! After the restart it again goes into your normal lock screen awaiting you! Updates ARE installed and Restart HAS been accomplished. you can log on and instantly start working or surf the net, or whatever you normally do!!
God Luck, hope this helps you and any others reading this!!