Amazon EC2 - Amazon Web Services offers reliable, scalable, and inexpensive cloud computing services. Free to join, pay only for what you use.
Datahike - A durable datalog database adaptable for distribution.
Microsoft Azure - Windows Azure and SQL Azure enable you to build, host and scale applications in Microsoft datacenters.
Datomic - The fully transactional, cloud-ready, distributed database
DigitalOcean - Simplifying cloud hosting. Deploy an SSD cloud server in 55 seconds.
Matisse - Matisse is a post-relational SQL database.