Check out this list:
1. Appirio Appirio is betting on helping companies move their entire IT infrastructures to the cloud. The 2-year-old startup specializes in cloud integration, migration, application development, and consulting services, and it offers Web storage and applications to sync data between cloud services.
2. Coghead Application development and hosting, also called platform as a service (PaaS), offered from Amazon Web Services. Includes authoring, workflow, and data integration capabilities. Founded 2003.
3. CohesiveFT CohesiveFT provides "Servers As A Service." Called elastic servers, Cohesive describes the concept as a custom-configured, on-demand virtual server.
4. Elastra Elastra straddles the line between public and private clouds. Its Elastra Cloud Server--a software bundle for designing, deploying, and managing cloud applications--can be used to deploy databases in Amazon's Elastic Compute Cloud, and Cloud Server will work in similar fashion inside data centers once an enterprise version tuned for VMware virtual machines is released in a few months.
5. Engine Yard Ruby on Rails developers want to focus on writing Web applications, not on the underlying software and systems needed to support them. Engine Yard's Ruby-in-the-cloud service lets them do that.
6. Enomaly Enomalism 2.0 elastic computing platform provides open source application development and deployment capabilities that can be used, among other things, to move virtual machine images to and from Amazon EC2 servers. Founded 2004.
7. Heroku Provides a Ruby on Rails development and hosting service, still in beta testing, based on Amazon's EC2. Founded 2007.
8. Hyperic CloudStatus performance monitoring service is in beta. It monitors the performance of applications in Amazon Web Services and Google App Engine. Founded 2004.
9. Intridea Based on Amazon's EC2, Scalr is an open source hosting environment with pre-built images for load balancers, databases, and application servers. Founded 2006.
10. Joyent Offers servers, storage, and other on-demand virtual infrastructure, called Accelerators, from its own data centers. Founded 2004.
11. Kaavo The first thing you should know about Kaavo is that it was founded by a former IT pro. The second thing is that its cross-vendor cloud-control software, called Infrastructure and Middleware On Demand, is used to set up and manage IT resources in the public cloud.
12. Layered Technologies Provides on-demand dedicated servers in a variety of configurations running Linux, Solaris, or Windows, plus Microsoft (NSDQ: MSFT) Hyper-V virtual servers as a hosted service. Founded 2004.
13. Mosso A division of Rackspace, Mosso competes with Amazon's EC2 in offering Web application hosting with on-demand compute cycles, disk space, and bandwidth. Founded 2006.
14. Nirvanix Businesses don't generate their own electricity, and Nirvanix CEO Patrick Harr argues they shouldn't have to provide their own storage, either.
15. ParaScale ParaScale's Cloud Storage software creates a clustered storage environment on Linux servers for public or private clouds. Founded 2004.
16. Relationals Offers an application hosting service called LongJump. A new Java-based development suite can be used to develop applications that are hosted on LongJump. Founded 2003.
17. RightScale RightScale lets customers deploy server instances in the Amazon cloud using prepackaged software components, then monitor those instances.
19. Skytap Skytap's goal is to make serving up virtual machines over the internet as ubiquitous as delivering HTML to a browser. The company's initial product is Skytap Virtual Lab, which offers virtual infrastructure on demand, a pre-populated software library, and more.
19. 10Gen Linux-based grid management software that includes an object database, application server, and SDK. Also hosts the apps. Founded 2008.
20. 3Tera AppLogic grid operating system runs on commodity servers connected via Gigabit Ethernet and can be used for public or private clouds. Founded 2004.