There are 2 interesting articles about Smartphone and Pocket PC Development on the MSDN site. The first one is:

Northwind Pocket Service: Field Service for Windows Mobile-Based Pocket PC
Summary: Learn about enterprise mobile solution business aspects and how to develop mobile enterprise applications for Windows Mobile 2003-based Pocket PCs using Visual Studio .NET, .NET Compact Framework, and the Windows Mobile 2003 SDK. The source code in this white paper implements server components, database, and a Pocket PC client. (58 printed pages)

Next We have:
Northwind Pocket Service: Field Service for Windows Mobile 2003-Based Smartphones  
Summary: Learn how to develop mobile enterprise applications for Windows Mobile 2003-based Smartphones using Visual Studio .NET, .NET Compact Framework, and the Windows Mobile 2003 SDK. The source code in this article implements server components, database, and a Windows Mobile 2003–based Smartphone client. (38 printed pages)

Both are very interesting articles. they go into SQL Server CE, syncing the data from the PPC or Smartphone DB to the main server. it also goes into design and everything else. Very infomitive.