Can people port an existing database to Database.com?
Yes. Developers can migrate existing databases to Database.com by either writing migration scripts using our metadata APIs or through 3rd party migration tools like Informatica Cloud who offers a tool to automatically migrate on-premise database schemas and data to Database.com. For more information on Informatica Cloud, see http://www.informatica.com/cloud.
What is the pricing for Database.com?
Database.com will be free to get started. Basic Database.com services, including database access, file storage and automatic administration, will be available beginning at:
Free for 3 users, and up to 100,000 records and 50,000 transactions/month
When will it be available?
Database.com is currently available as part of salesforce.com’s Sales Cloud, Service Cloud and Force.com offerings.
In 2011 customers will be able to subscribe to Database.com as a stand-alone product. Later in the year the new Database.com administration and development console will be available.
Salesforce's Database.com and Force.com: Differences?