A colleague of mine, Michael James, just posted his Introduction to Scrum video on YouTube I think is the right length and depth for an overview - it's not so short as to be trite (or worse, incorrect), but it's not an exhaustive examination of Scrum either. This video is good prep for people who are planning to enter a CSM class and don't want to go in cold.
On October 27th, I co-presented the webinar, “A Marriage Made in Heaven: Agile and Project Portfolio Management”, with Russ King, Vice President, Product Development, Results Positive, Inc. and Caleb Brown, Systems Engineer at CollabNet.
The Scrum Alliance has published a new whitepaper called “Coaching is Key for Scrum Success” which outlines some of the problems organizations face when implementing Scrum, how Scrum coaching can help, and what to look for in a Scrum coach. Most organizations run into issues when first implementing Scrum. Rather than let these problems continue to plague the Agile implementation and jeopardize the risk of success, many organizations find that working with a Scrum coach early in the process helps to avoid “Scrum-But” and reverting to old ways of doing things.