In reality, there are organizations which have functional or product manager roles which do not fit under the traditional roles defined by agile methods. Jurgen Appelo started a thread (on his blog) to capture the best practices for a newly minted agile manager.
Here is what I think (as interpreted from the Agile principles)..please add on if I missed anything important
An agile manager should:
- Focus on optimizing the "business value" being delivered by the agile team. You may decide on your own metrics for business value (qualitative, quantitative or gut feel), but key is to have a sense ..at all times
- Pursue delivery of a fully working software at end of each sprint
- Periodically (pick your own frequency) Review and optimize the 'Done' list
- Identify key stakeholders and ensure their participation (as required) during the entire project life cycle
- Set expectations clearly (with all stakeholders), manage expectations to avoid last minute surprises
- Make an genuine effort to understand all aspects of the project (example: if you are not technical, don't avoid the architecture all together, try to gather just enough understanding)
- Set up information radiators (to convey real time information to all stakeholders)
- Focus on attaining a sustainable velocity quickly and early in the project life-cycle (it helps in planning and avoids burn outs)
- Watch out for 'Smells' (things which might be an impediment to agile practices
Last but not the least, an agile manager should demonstrate thought leadership and show genuine concern for professional growth of each member of the team. It's essential for the agile manager to win the respect of the team. You would always be better of by being a 'Leader' rather than a 'Manager'