Enterprise Cloud Computing refers to a computing environment residing behind a firewall that delivers software, infrastructure and platform services to an enterprise. Cloud computing also typically delivers Web services, providing access to components that can be easily combined to rapidly create composite web applications to meet the ever changing needs of a business operation.
IaaS : Amazon EC2, Rackspace
PaaS : Windows Azure, Google app engine, Force.com
Private Cloud : OpenStack, vmware vCloud, Eucalyptus
Cloud & Instance Management : BMC Cloud Lifecycle Management (CLM), Puppet, Chef
Cloud Monitoring / Log Analysis : Neustar, Pingdom, nagios
Enterprise Cloud Infrastructure / Virtualization : VMWare