Jeff Blankenburg has produced a great quantity of blog posts about developing for Windows Phone 7. Now he's supplementing that with an all-in-one resource page that links out to a ton of great material in addition to his own. Oh I know, you might not need to see the TV ads to learn how to develop for the thing, but I appreciate the link anyway. If you're doing phone work, or thinking about it, this list is for you.
Kate