I find that portfolio management is one of the most misunderstood or simply ignored part of project management.
And unless an organization only has to care about one project, it is important to understand portfolio management.
Here is an introduction video on Project Portfolio Management, from ProjectManager.com. Please note that Projectmanager.com is an interesting and useful source of information.
https://www.facebook.com/projectmanage
http://twitter.com/projecttips
