Ronald Bradford is a busy man. He has just finished Effective MySQL: Optimizing SQL Statements, the first in a series of MySQL books. There is a sample chapter at the link above.
The chapters on indexing will be valuable to novices. Ronald has distilled his presentation on the use of EXPLAIN into chapter that should be made mandatory reading. The book is free of fluff and full of information that you will reference well after the initial reading.
For those of you at Oracle Open World, this book and others are heavily discounted in the bookstore on the second level of Moscone West, near the MySQL Community Kiosk.