Cloud computing looks to be a "classic disruptive technology," says Forrester Research in an interesting new report published this week. For enterprise IT shops, cloud computing still poses some real risks, including an almost complete lack of service-level agreements and customer references, plus some genuine security and compliance concerns, according to Forrester. But even so, IT shops are tapping into cloud services for targeted projects: "There's a high likelihood that developers inside your company are experimenting with it right now," writes senior analyst James Staten in the report,"Is Cloud Computing Ready for the Enterprise?"

That analysis meshes with what we recently reported hearing from CIOs in "Cloud Computing: Tales From the Front." The cloud isn't new per se; enterprise IT has had access to the Internet and software-as-a-service for years. But now, some vendors are giving enterprises the chance to run not only hosted apps but also custom-developed apps in the cloud--with great flexibility to scale computing power on short notice, and to pay only for what computing power is used. Enterprise IT sees the promise and is experimenting, cautiously.

Which cloud computing vendors should be on your radar screen now? In its report, Forrester cites 11:

1. Akamai

2. Amazon

3. Areti Internet

4. Enki

5. Fortress ITX

6. Joyent

7. Layered Technologies

8. Rackspace

9. Salesforce.com

10. Terremark

11. XCalibre