Reading the other posts I probably think im one of the few teachers here with a view on cloud computing.
I hear a number of people talking about bandwidth concerns - yes this certainly is an issue but if one looks at how many bandwidth upgrades there have been for schools since 2000 and try and extrapolate that forward, by the time cloud computing is a lot wider in use and stable (middle of next decade?) the bandwidth may have caught up to support it.
I know one has to be lucky working at schools with stable net connections, but if I look back at the last 5 years Ive had my gmail account, apart from pure loss of internet connection gmail has itself been 'down' far less then the school networks I have been working on. In other words local school networks in my own experience have a far higher failure rate then cloud services i have used.
I will be advising my own SMT that for the next few years cloud computing is not a must have - the only possible service which should be considered is email through something like Google (and perhaps only as a cost cutting measure)
I still feel though it should be a good idea to plan for the possible introduction of more cloud based services at school. I know as a teacher one thing which frustrates me is pupils who forgot to attach their latest version of their coursework to their emails when sending it back from home. Google docs type services or even virtual drives would help keep things a whole lot simpler.
I agree with Dhicks that will probably start appearing is more stable combinations of online/offline methods of managing data - mini local clouds so to speak.