Dear Sonu,
As your score is of 211 marks in IIT JEE 2010, so with these marks your estimated rank would be some where in between 4500 to 5000. According to the calculation chances are less that you can get any expected branch in of the IIT's . Now as you said that you are intrested in cs or maths so with rank possibility is less that you can get them inti IIT'S.
As your score is good i.e around 281 which would lead you to the estimated rank around 2000 , so with this rank definately you can get any of the NIT's with your desired branch.
However score may vary and as a result rank may also vary, a slight difference may create lots of difference in rank.
For further details you can visit the following:
http://www.askiitians.com/aieee-2010/aieee-2010-cut-offs.aspx
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all the best.
thanks and regards.
Akhilesh Shukla