I would say follow the SCWCD Links page for books, mock exams, notes and other useful stuff. The latest version is SCWCD 1.4 and there is no version 5 planned as far as anyone here knows. You can find further details through your local Sun website (or Sun.com training); good study guides also include details of the exam format.
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / AmazonAmazon UK )