Sign up today for the free (signup required) Beta of SQL Server Data Services (SSDS). SSDS are highly scalable, on-demand data storage and query processing utility services. Built on robust SQL Server database and Windows Server technologies, these services provide high availability, security and support standards-based web interfaces for easy programming and quick provisioning.
From the FAQ:
SQL Server Data Services is a storage and query processing utility providing mega scale, high availability, reliability, and geo-distributed data services in the Cloud. Customers use the service on-demand, with no up-front cost. It eliminates the initial investment in hardware and software and the on-going cost for storage administration, scale maintenance. Developers and Service providers can quickly run their on-demand applications with minimal infrastructure cost.
Target Customer Scenarios:
TONYSO : Free Microsoft Database in the Cloud (Beta): http://blogs.technet.com/tonyso/archive/2008/03