From Microsoft Press web site

After the release of Moving to Microsoft Visual Studio 2010 in September, here’s an updated list of some of our free eBooks:

Free eBook: Moving to Microsoft Visual Studio 2010 (10 chapters by Patrice Pelland, Pascal Paré, and Ken Haines)

Free eBook: Introducing Microsoft SQL Server 2008 R2 (10 chapters by Ross Mistry and Stacia Misner)

Free eBook: Programming Windows Phone 7 Series (DRAFT Preview) (6 chapters by Charles Petzold)

Free eBook: Petzold’s Programming Windows Phone 7 (Special Excerpt 2) (newer than the eBook above; 11 chapters by Charles Petzold)

Free eBook: Own Your Future: Update Your Skills with Resources and Career Ideas from Microsoft (8 chapters by Katherine Murray)

Free eBook: Understanding Microsoft Virtualization Solutions (Second Edition) (6 chapters by Mitch Tulloch)

Free eBook: First Look Microsoft Office 2010 (14 chapters by Katherine Murray)

Free eBook: Windows 7 troubleshooting tips (short eBook by Mitch Tulloch)

Free eBook: Introducing Windows Server 2008 R2 (9 chapters by Charlie Russel and Craig Zacker)

Free eBook: Deploying Windows 7, Essential Guidance (10 chapters from the Windows 7 Resource Kit and 6 TechNet articles)

We hope there’s something in this list for you to use and enjoy!