This certification is very easy to pass if you have the understanding of design patterns. Understanding does not means that you know the definition of patterns, but it means you did some Java EE based application designing in past and applied various patterns. This will going to help you in answering patterns related questions as well as architecture related questions.
So if you have above experience then half of your battle won. And if you haven't done then its better to hold your horse and wait for some time .... some application design & apply patterns. "Practical experience is must" .......
Other things which you need to study like application security parameters, design consideration of thick client, EJB 3.0 usage, presentation framework, and application integration techniques.
Few good study materials are:
1. The Java EE 5 Tutorial, Third Edition (http://java.sun.com/javaee/5/docs/tutorial/doc/JavaEETutorial.pdf)
2. Core J2EE Patterns: Best Practices and Design Strategies, Second Edition
3. Java Design: Objects, UML, and Process
4. Designing Enterprise Applications with the J2EE Platform
5. Enterprise Integration Patterns
6. The Java EE 5Tutorial - For Sun Java System Application Server 9.1
7. Sun Certified Enterprise Architect for J2EE Study Guide
8. Core Security Patterns: Best Practices and Strategies for J2EE, Web Services, and Identity Management
For SCEA Part 2 & 3, refer my next article.