I am an Indian student on F1 visa and have been filing 1040 NR-EZ from 2003 onwards. I am wondering if it is possible to file amendmnet (1040X) to my this year's and previous years return and choose to be considered as resisent for tax purposes to get educational credits to maximise my return.
Thanks for your advice!

Negative. Your previous filing as a non-resident alien was the CORRECT way to file.

To change it to resident status knowing that it is incorrect constitutes TAX FRAUD, which is a CRIME in this country.