12th is the official launch of Windows Phone 7. There’s an MSDN Simulcast event available which is a full day of training on writing Windows Phone applications.
There are also free in-person events around the country. You can learn about them at http://www.msdnevents.com/wp7devlaunch. Unfortunately the Portland one is already full.
Dislaimer: I think this is a great opportunity, but I also put this on my blog for the chance to win a phone. Info.