SQL Server Compact Edition 3.1 launched
Microsoft SQL Server 2005 Compact Edition is the next version of SQL Server Mobile adding the desktop platform. SQL Server Compact extends the SQL Server Mobile technology by offering a low maintenance, compact embedded database for single-user client applications for all Windows platforms including tablet PCs, pocket PCs, smart phones and desktops. Just as with SQL Server Mobile, SQL Server Compact is a free, easy-to-use, lightweight, and embeddable version of SQL Server 2005 for developing desktop and mobile applications.
SQL Server Compact Edition 3.1 (SSCE in short) being successor to SQL Server Mobile Edition offers same capabilities as SQL Mobile and lot more. You will need VS2005 SP1 to take advantage of its integration with Visual Studio.