Interest in cloud and virtualization

I am gaining an interest over the past few years, in cloud technologies. I work for Zenoss Inc, a systems monitoring product. Zenoss monitors cloud resources that I help support, and I have recently implemented Zenoss out in an amazon ec2 instance. Next hoping that I can use their VPC technology, a method to use a VPN-like connection to make your local enterprise network think that the cloud server is internal to your private network. That way I can get the cloudbox to monitor internal resources, yet is implemented out in the public cloud. I am starting to realize that amazons ec2 and rackspaces cloud solution are basically hosted virtualization solutions - like vmware is a private virtualization solution.

Some questions that I want to find more information on, are: What cloud, virtual, saas, iaas solutions do others use for customers or internally? Do you mostly implement saas solutions for small companies (vs not as much for large customers)? I hear that Microsoft is getting into the cloud atmosphere. I am not a huge microsoft fan, but am interested to see what they are doing. I am curious as to how cloud technologies can be more than a flash in the pan, and truly propel our society.