ESE API at MSDN: http://msdn2.microsoft.com/en-us/library/ms684493.aspx New features in ESE for Vista/Server 2008: http://msdn2.microsoft.com/en-us/library/aa964797.aspx ESE overview http://technet.microsoft.com/en-us/library/aa998171.aspx Wikipedia...

A good overview of SQL Server 2005 Compact Edition http://msdn2.microsoft.com/en-us/library/bb380177.aspx