I passed the SCWCD Exam about a year ago. I thought it was much easier than the SCJP. I only used the following book
SCWD Exam Study Kit: Java Web Component Developer Certification Authors: Hanumant Deshmukh and Jignesh Malavia
If you can answer the review questions at the end of each chapter you should pass. I was rushed to get the certification, and got an 81% with about 7 days of studying. If you currently work with Tomcat, JSP and Servlet then this is not a hard exam. If you are using the certification to learn JSP/Servlet then you may need a little longer than a week. Did I mention I thought this exam was easier than the SCJP 1.4 exam.