see for getting into iit even if you are nri or foreign national you will have to write jee and clear it with a good rank and you will have to compete with a generl indian candidate as there is no special reservation for foreign ational. Now th situation in india is that each and every candidate who gets selected in jee undergoes an intense coaching curse from a coaching center for 2 long year besides his normal school studies. Even the topper of jee who is considered to be a genius also takes coaching or tution for 2 long yearrs fromm kota. So if you think that you can clear jee with a good rank  then think again. But the nit's (national institute of technology ) in india teakes foreign students or nri through dasa schme and you can enetr these colleges directly without passing any test on the basis of your 12 class score. Nits comes second to iits. and as far as i rememberuptill now only one foreign national from dubai i suppose has been able to  clear jee and that too with not so good rank..

But still dont loose hope you can try..

best of luck..

you can mail me at polqws@yahoo.com