J. David Eisenberg has written SVG Essentials, published by O'Reilly & Associates this month.
SVG Essentials covers all the features of the W3C's Scalable Vector Graphics technology, paying particular attention to the foundational elements of SVG.
Later chapters cover animation, and the creation of SVG using programming languages.
A sample chapter is available online.
Eisenberg has also written An Introduction to Scalable Vector Graphics, published online at XML.com.
Related links:
Disclosure: several xmlhack editors work, or have worked, for O'Reilly & Associates.