"There is an understanding that GREAT TEAMS build GREAT SOFTWARE and those teams should be trusted and empowered to deliver. A GOOD AGILE Project Manager (PM) is an enabler of the team. The Agile PM helps the team STAY FOCUSED on the larger business issues and REMOVE OBSTACLES that impact the team’s ability to deliver. The focus is on the team because ultimately the team is on the hook for delivery."
http://www.agiledad.com/Documents/BAWhitepaperJune.pdf