Every spring there is a tulip festival up north of Seattle, WA. It reminds me that in the spring everything is new.
Most Enterprise organizations are still exploring/piloting agile. In these organizations team members are not typically mature in their ability to self-organize. The Project Manager’s role becomes one of helping teams learn how to self organize. (http://whitewaterprojects.com/2010/03/30/self-organization/).
Enterprise agile operates differently than agile in a software company. In a software company the whole company is in support of the software being developed. Roles like the Product Owner make complete sense and are easy to explain. The entire company drives the software development, the marketing department supports the software, the sales department supports the software, the strategic planning department supports the software. In an enterprise organization implementing agile in an IT department, the tables are completely turned. The software is in support of the company: the Software supports the marketing, sales, or strategic planning, not the other way around. Roles like the Product Owner are still valid but are not a simple natural fit and need explanation and education. The project manager in the enterprise agile organization operates in the space between the project team and the rest of the enterprise. Acting like a buffer to protect the team, including the ScrumMatser if you are using scrum, from the politics of the company. Often, agile development is being executed in a pocket of the overall project and the project manger is the bridge between the agile team and the rest of the work: training, marketing, sales, go to market planning, etc…
Additionally, the PM needs to be less of a dictator of tasks and tracker of task completion and moved to a more strategic position that deals more with long range planning, communication with external dependencies and active expectation management. I see the PM participating in a choreographed dance with the ScrumMaster, They both are Roadblock Removers for the team. The ScrumMaster removes internal development roadblocks, while the PM removes external organizational and political roadblocks.