Link tip: Windows Phone 7 Developer Guide

During the summer, I've received a couple of questions from developers about good Windows phone training material. Now that the Mango release is hopefully soon out, and Mango pre-release material already appearing under MSDN Library, I wanted to post a link to a slightly more hidden piece of documentation called the Windows Phone 7 Developer Guide.

This guide is written for the original 7.0 release, but even so, it is a highly useful resource even after Mango is ready. The reason why this piece of documentation is hard to find is that it has been posted under Patterns & Practices. Thus, most developers would probably skip the section and instead look from the more traditional place in the library.