I'm continually astounded about how few organisations really care about communicating with their staff.
When communications campaigns are put up for marketing awards it's almost as if internal communications doesn't exist as an objective for anyone.
For most organisations their staff are potentially thousands of people (or in the case of the NHS over a million) who, every day, have the opportunity to market their organisation - not just to customers but to their friends, neighbours and acquaintances.
Within major organisations there's usually a communications hierarchy where the press office is closest to the board, marketing is somewhere in the middle and internal communications is often left to the human resources department.
All the exceptions I've come across either result from an organisation that genuinely believes that staff are the future of it (e.g. the John Lewis partnership) or where the Chief Executive realises the value of it (e.g. Allan Leighton's internal Ask Allan blog at Royal Mail).
Anyway this is a convoluted way of saying that there's a great blog post on this at Hill & Knowlton's Collective Conversation blog here.