I was reading Daniel Moth's blog post about What's New in the .NET Compact Framework 3.5 which is part of the Orcas Beta release  (next version of Visual Studio) and I learned about his new book, Microsoft Mobile Development Handbook, just published with 600+ pages of what seems to be great content

  

The 18 chapters cover the following topics:

1. .NET Compact Framework—a Platform on the Move
2. Building a Microsoft Windows Forms GUI
3. Using SQL Server 2005 Compact Edition and Other Data Stores
4. Catching Errors, Testing, and Debugging
5. Understanding and Optimizing .NET Compact Framework Performance
6. Completing the Application: Packaging and Deployment
7. Exchanging Data with Backend Servers
8. Networking
9. Getting Connected
10. Security Programming for Mobile Applications
11. Threading
12. Graphics Programming
13. Direct3D Mobile
14. Interoperating with the Platform
15. Building Custom Controls
16. Internationalization
17. Developing with Windows Mobile
18. Introducing .NET Compact Framework Version 3.5 and Visual Studio "Orcas"

Get it from Microsoft Press http://www.microsoft.com/MSPress/books/authors/auth10294.aspx