SCRUM Master's Cheat Sheet
Check out www.mountaingoatsoftware.com/scrum/.
Excellent "by the book" description of SCRUM practices. Daily Scrum, Product and Sprint Backlog, roles of Product Owner, Team and Scrum Master, Sprint Planning and Review and so on - all well written, illustrated and concise. If you are a Certified SCRUM Master (CSM), this is a great reference to refresh your own mind or share with team mates and project community.
Some SCRUM related resources are also available for download.
Mike Cohn, the Mountain Goat Software founder, is known by his book, "Agile User Stories Applied"