Wired.com/cloudline has just posted an interesting article, by Dr. Angel L. Diaz from IBM, on the importance of a Service Level Agreements (SLA) for your Cloud Services (http://www.wired.com/cloudline/2011/12/service-level-agreement%E2%80%99s-in-the-cloud-who-cares/).
The article talks about some of the pitfalls of not having a SLA and potential considerations you need to take into account to minimize the risks of adopting cloud as an extension of your IT shop.
It should also be noted that the Cloud Standards Customer Council (http://www.cloud-council.org/) just launched a new work group to develop the Service Level Agreement Cookbook. This effort will be a deep dive into the elements of a SLA and to provide an example of a SLA for use by both cloud consumers and cloud providers.
Add your voice and your requirements to the SLA Cookbook activities by joining the Cloud Standards Customer Council (http://www.cloud-council.org/membership-application.htm) and the SLA Work group.