Hi Reddy,
I agree with the comments above -
you should try and get all the developer certifications, as it will make you are more rounded developer.
In case it was not obvious in the above posts, the SCJD is a project based certification. You have to write code for client and server applications based on (badly written) specifications provided by Sun. You have to hand the assignment in to Sun and then wait for someone to grade it. Some people have waited over six weeks to hear whether they passed or not.
SCJP, SCWCD, and SCBCD are all theory based, where you turn up to your local
testing site, do a multiple choice exam, and get told instantly whether you passed or not.
So if you want to have something quickly that you can show your loved ones / employers (rarely the same thing

) then you might want to look at SCWCD or SCBCD. Likewise if you enjoy pure theory exams rather than practical then the SCWCD or SCBCD are more your style.
On the other hand, if your goal is to get all three (SCWCD, SCBCD, and SCJD) in the shortest total elapsed time, then you might want to start with SCJD, as you can then continue with the other two while you wait for your results from SCJD. Likewise if you want a break from the theory and want to get your hands dirty in a
real certification, then do the SCJD first.
The book Bharat mentioned (
SCWCD Exam Study Kit by Hanumant Deshmukh, Jignesh Malavia, Jacquelyn Carter) is the best one I know of for SCWCD. I am keeping my copy of it around, even though I don't do much web development work, just because it is such a good book.
The best book I know of for SCJD is
The Sun Certified Java Developer Exam with J2SE 1.4 by Mehran (Max) Habibi, et al. Max is a regular contributor in this forum, and until very recently was one of the bartenders in this forum.
And for SCBCD I would recommend
Head First Ejb: Passing the Sun Certified Business Component Developer Exam by Kathy Sierra, Bert Bates. It's not quite out yet (any week now), but I think you can't go wrong with a book written by the exam's authors
(Phil - I am not touching your comments. We have Max on our side if any of those SCWCD weaklings start getting rowdy

)
Regards, Andrew