This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
Sun does call SCJA an "entry certification," but it is not "the" entry point. In particular, the SCJA exam is not required for the SCJP exam, which has no exam prerequisites. As for choosing one over the other, you might be interested in this thread.