Edam - did you see my link earlier in the thread. It includes some ideas for making money from digital media (might be in the follow on comments).
One idea is fully utilising the value of the Guardian brand. Which roughly translates as getting more money from it's customers. This can be either directly (getting customers to pay for extra's) or indirectly (selling info about valuable customers to third parties).
But, both of these methods would require a cultural shift for the Guardian.