There isn’t much to say really. The Windows Phone 8 SDK has finally been released for all of us hungry developers. You can download it here right now: http://www.microsoft.com/en-us/download/details.aspx?id=35471
Also get all of the latest news on Windows 8 and Windows Phone from BUILD 2012. Brilliant for discovering how to get your apps using the two platforms and getting ready for marketplace!
Enjoy developing for Windows Phone 8 just as much as I will! I hope to see all of your awesome apps on the marketplace.