Hello
To help Gregg Bolinger picking "Pro Spring" or "Spring in Action", I suggest:
Sample Book Chapters at SpringHub.com which includes Chapter 4 of "Pro Spring" and Chapter 1 of "Spring in Action".
To answer Ashik Uzzaman
>Does any book of Spring yet cover Spring Web Flow?
Yes, there is an upcoming 300 pages book to be published on January 2006! "Expert Spring MVC and Web Flows" (Expert) (Paperback) by Seth Ladd, Keith Donald