80% of IT Infrastructure in the cloud by 2015?

Lately I've been in the cloud a lot. From Google's app engine, sales-force.com, Amazon's Elastic Compute Cloud (E2C), to Microsoft's Live Mesh, we hear about the cloud a lot.  More and more people are signing up for on-demand applications (We, as a small business, also use on-demand applications) and almost every other IT start-up that I talked to is a Saas of this or that. So the trend is clear, the question is are you ready?