Very cool! This is useful for small deployments. We developed PlanForCloud.com to help with cost forecasting for big deployments, where you want to compare infrastructure options and cloud providers.
Also, don't forget that one of the key benefit of using the cloud is elasticity, and unless you model this, you won't get accurate estimates. We developed the notion of elasticity patterns[1] to let users do this, so you can say something like "my baseline S3 storage is 100GB, but every month this grows by 5% and in the Christmas it doubles".
Also, don't forget that one of the key benefit of using the cloud is elasticity, and unless you model this, you won't get accurate estimates. We developed the notion of elasticity patterns[1] to let users do this, so you can say something like "my baseline S3 storage is 100GB, but every month this grows by 5% and in the Christmas it doubles".
[1] http://www.planforcloud.com/pages/docs/patterns.html