I posted the following video about Scrum on Youtube.
I have made sure it is compliant with the Scrum guide 2011 which altered Scrum.
Many other Youtube videos about Scrum are out of date or incorrect.
Scrum video on Youtube 2012 Scrum update compliant
The following video describes a new way to look at uncertainty and how using iterative and incremental estimation and work to produce a working product increment.