The CTP published 9-Jun-06 can be downloaded from here. In the overview's own words:
Microsoft SQL Server 2005 Everywhere Edition (SQL Server Everywhere) is designed for developers who need light weight, in process relational database solution for their applications that can be developed and deployed on desktop as well as on mobile devices. The SQL Server Everywhere CTP contains the runtime bits that can be used to develop and deploy applications on desktop only. The RTW of SQL Server Everywhere will contain the device support for developing and deploying applications on mobile devices.