David Hobbs published a nice post describing how to define a work program for managing your website. The role of website product manager is near and dear to me. In fact, in my CMS Selection and Content Management Assessment projects, I get concerned about long term success if the client has not designated and empowered a strong product manager and a established a disciplined product management process.
What I like about David's process model is that it shows the components of the process and how competing requirements work through that process. The diagram is a nice visual for a product manager when receiving requirements and setting expectations.