Thanks to all of you RANCHERS!!! for the support you gave me!
K & B Book was the best!! It helped me greatly!!! All the questions were closely related to the concepts in this book and questions were also resembling the same format at the "back of chapter questions".
Apart from that "Khalid A.Mughal " book also help me. There are very good practice questions in each chapter. It has a good mock exam in the end also!
The mock exams gave me confidence, the real exam questions were easy compared to the mock questions i practiced. Some of the mock exams i practiced are, ExamLab for SCJP 6.0(real tough!, but worth taking), Niko's mock and other free mocks from Java Ranch site. I got around 55 to 65% in ExamLab, and around 70 - 80% in rest of the mocks.
Most importantly i practiced the end of chapter questions in K&B book again!!
For SCJP 6.0 i purchased the "Sun Certified Programmer for Java 6 Study Guide" by Kathy Sierra & Bert Bates.
I dont think you can use SCJP 5 book to prepare for SCJP 6.0 as there are new topics added to scjp 6 version, i would recommend you to purchase the SCJP 6.0 book for K&B. I mainly studied the K&B book only. I took 2 months to prepare. Please note the time to prepare differs for everyone, I would say the more you are comfortable with the mock exams score after study, will give you an idea about when to take the exam.
You can get the details about SCJP 5 and SCJP 6 syllabus in the links given by Ankit.
hope this helps.