Toby Ward of Prescient Digital Media has a couple of really good models on what it takes to have a successful intranet. Specifically:
You can read more about them in his article Intranet Planning: An Intranet Model for Success. Great stuff -- and very close to home as well because, at MBS, we're in the middle of rolling out our new intranet portal. In fact, the first phase of our project is in the Implementation and Marketing stages of Ward's project methodology model. Exciting times, indeed.