We mentioned how developer Jeff Blankenburg was doing a 31-Days of Mango tutorial via his blog a few weeks ago. The idea was to publish a tutorial about specific app development on Windows Phone every day, giving a kind of boost for newbies out there as well as some tips for those with previous experience.
Now you can take the whole series with you on the go via the app, which is kind of meta when you think about it. The app does fetch for $0.99 and considering all the knowledge you're getting, seems like a fair offering for the man. Pick it up here in the Marketplace.