Psst! Mister. You wanna buy some cloud? Cloud computing that is. It is the wave of the future in the delivery of everything from computer software to media products to computer services. Market researcher The 451 Group estimates that revenue for infrastructure as a service, one of the two big categories of cloud computing will grow to $1.2 billion a year by 2013 from $200 million last year. Data storage in the cloud, the other big cloud computing segment, will see revenue climb to $1.7 billion in 2013 from $150 million in 2009, the group estimates.