SQL Server Compact 3.5 Books online (SQL 2008)
SQL Server Compact Edition is best used with handheld devices such as PDAs to get update on the sales & marketing information within your SALES department that is spread across the globe. As in the name it is compact database ideal for embedding in mobile and desktop applications. SQL Server Compact 3.5 gives developers a common programming model with other SQL Server editions for developing both native and managed applications.
With current trend of CTP for SQL Server 2008 Microsoft has been working on CE release too, before you want to further about this edition better to review the links below:
SQL Server Compact 3.5 Concepts
SQL Server Compact 3.5 Development Guide
SQL Server Compact 3.5 Technical Reference
Architecture (SQL Server Compact 3.5)