plz tell me that is it worth to drop 1 year for iit jee

You need to give more details about yourself before we can actually advise you on that. How did you do in AIEEE and/or any other competitive exam?
You must consider all alternatives before deciding on anything.

i score only 30 marks in aieee i think if i prepare for next year then i can crack jee 2011

yeah sure Gagan!! if you are confident about it and ready to work hard for it then you should definitely try for it next year. nothing is impossible!!!