Microsoft evangelist Mike Ormond this week announced the availability of an intriguing new free eBook for developers interested in Windows Phone. Dubbed Building Windows Phone Apps: A Developer’s Guide, the book is over 100 pages long and is written by a team of platform experts.

"'Building Windows Phone Apps: A Developer’s Guide' is a community effort to capture useful information and learning about building apps on the Windows Phone platform," Ormond writes in a blog post. "I'm pleased to announce that the 1st edition is available for download today."

"This is an organic effort – more chapters will be added and chapters will be updated as and when contributors choose to do so. I have a number of additional chapters in my inbox at the moment – expect those to be edited and included in the 2nd edition in the near future," he adds.

The book looks great already. Here's the TOC:

Introduction
The Windows Phone Developer Tools
The Application Lifecycle
Accessing Phone Features (launchers, choosers and input features)
Location Aware Applications and Mapping
Reactive Extensions for .NET
Marketplace – Designing for First Time Approval
A tour of libraries and samples

You can download "Building Windows Phone Apps: A Developer's Guide" for free from Lulu.