Some more sites on Certification :
Sun's site
Java Certification and Reference
Java Study Group
Java Certification Head QuartersThey also have a discussion group at Earthweb Discussions - and the newsgroup is earthweb.gocertify.java
Sun Java Certification - Organized by Topics
Focus on Java Certification - The Mining Co.
Old website or SCJP Revision Guide
Java Sun Certification
Java Certification Study Guide - notes
Java Programmer Certification Notes
Free Java Certification Training
The Java Skinny
Guide to Certification
Java Certification
Java Study Notes
Information about SCJP, SCJD, SCJA
Free online course
Theoritical Question and Answers related to Java Certification Applied Reasoning's Java Certification Mock Exam
Java Tidbits
Jahann's Java Home
Vivek's home page - Notes and links to mock exams
your tool for Java Certification

Exam simulators and training tools :
JCertify
Java 1.1 & 2.0 Certification Flash Cards
gEs : Java 2.0 Certification Exam Simulator
Exam Simulation program for the Sun Certified Java Programmer's Exam

Free Java Certification Book online :
Java 1.1 Certification Training Guide by Cary Jardin (print version got lots of bad reviews due to errors)

Some Free Java Books online for Reference :
It has some books on advance topics too