U gotta give GATE ... search for its details on websites ...
the form will come out in a month or two ...
you get them frm bank .. either sbi or canara ...
the last date to fill completed forms is around oct probably ..
and exam's usually conduncted in 1st week of feb ...
you need a percentile of atleas 99.7 or so ...
then there will be interview sometime around april ..
then u get into iit ..
the exam structure is divided according to depts ..
some parts are compulsary and others to be choosen ...
i dont know the very exact details ...
check this site out ..
*www.iitkgp.ernet.in/acadsnew/gate/home.php
or else post any other doubts ...
i may be of help