Iti recomand SQL Server Compact Edition.

[1]  website: http://www.microsoft.com/sql/editions/compact/default.mspx

[2] te inregistrezi si-l poti utiliza gratuit: http://www.microsoft.com/sql/editions/compact/redistribute.mspx

[3] download (database engine, books online - extensive developer documentation that explains how to create mobile and desktop applications using SQL Server Compact Edition , tools for Visual Studio 2005): http://www.microsoft.com/sql/editions/compact/downloads.mspx