Otherwise, SAS Press books by Carpenter or Burlew seem to be my students' favorites. You'd have to read a bit of the book on-line to see whose writing style you prefer.
I recently purchased 'SAS Macro Programming Made Easy' (ISBN: 978-1-59047-882-0) and have made pretty good use of it so far. I've found the book along with some of the SAS white papers make for a good combination.
I didn't have much, if any, macro programming experience before purchasing the book and have been able to get done what I needed to with the combination of the book and white papers.